List of New South Wales state by-elections

This is a list of by-elections for the New South Wales Legislative Assembly. A by-election may be held when a member's seat becomes vacant through resignation, death or some other reasons. These are referred to as casual vacancies.

• Brackets around a date (D/M/Y) indicate that the candidate was unopposed when nominations closed or that, as a result of an appeal against an election result, the sitting member was replaced by the appellant. These candidates were declared "elected unopposed" with effect from the date of the closing of nominations or appeal decision, and there was no need to hold a by-election.
• By-elections which resulted in a change in party representation are highlighted as: Gains for the Labor Party and its splinter groups in red; for the Liberal Party and its predecessors in blue; for the National Party and its predecessors in green; for independents and minor parties in grey; for the Free Trade Party in yellow and for the Protectionist Party in cyan.

Fifty-eighth Legislative Assembly 2023–2027
By-election	Incumbent	Party		Reason	Date	Winner	Party
Pittwater	Rory Amon		Liberal	Resigned	19 October 2024	Jacqui Scruby		Independent
Epping	Dominic Perrottet		Liberal	Resigned	19 October 2024	Monica Tudehope		Liberal
Hornsby	Matt Kean		Liberal	Resigned	19 October 2024	James Wallace		Liberal
Northern Tablelands	Adam Marshall		National	Resigned	22 June 2024	Brendan Moylan		National
Fifty-seventh Legislative Assembly 2019–2023
By-election	Incumbent	Party		Reason	Date	Winner	Party
Bega	Andrew Constance		Liberal	Resigned to contest federal seat of Gilmore	12 February 2022	Michael Holland		Labor
Monaro	John Barilaro		National	Resigned	12 February 2022	Nichole Overall		National
Strathfield	Jodi McKay		Labor	Resigned	12 February 2022	Jason Yat-Sen Li		Labor
Willoughby	Gladys Berejiklian		Liberal	Resigned due to ICAC investigation.	12 February 2022	Tim James		Liberal
Upper Hunter	Michael Johnsen		National	Resigned due to police investigation	22 May 2021	Dave Layzell		National
Fifty-sixth Legislative Assembly 2015–2019
By-election	Incumbent	Party		Reason	Date	Winner	Party
Wagga Wagga	Daryl Maguire		Liberal	Resigned due to ICAC investigation	8 September 2018	Joe McGirr		Independent
Blacktown	John Robertson		Labor	Resigned	14 October 2017	Stephen Bali		Labor
Cootamundra	Katrina Hodgkinson		National	Resigned	14 October 2017	Steph Cooke		National
Murray	Adrian Piccoli		National	Resigned	14 October 2017	Austin Evans		National
Gosford	Kathy Smith		Labor	Resigned due to ill health	8 April 2017	Liesl Tesch		Labor
Manly	Mike Baird		Liberal	Resigned	8 April 2017	James Griffin		Liberal
North Shore	Jillian Skinner		Liberal	Resigned	8 April 2017	Felicity Wilson		Liberal
Canterbury	Linda Burney		Labor	Resigned to contest federal seat of Barton	12 November 2016	Sophie Cotsis		Labor
Orange	Andrew Gee		National	Resigned to contest federal seat of Calare	12 November 2016	Philip Donato		SFF
Wollongong	Noreen Hay		Labor	Resigned	12 November 2016	Paul Scully		Labor
Fifty-fifth Legislative Assembly 2011–2015
By-election	Incumbent	Party		Reason	Date	Winner	Party
Newcastle	Tim Owen		Liberal	Resigned due to ICAC investigation	25 October 2014	Tim Crakanthorp		Labor
Charlestown	Andrew Cornwell		Liberal	Resigned due to ICAC investigation	25 October 2014	Jodie Harrison		Labor
Miranda	Graham Annesley		Liberal	Resigned to become CEO of Gold Coast Titans rugby league team	19 October 2013	Barry Collier		Labor
Northern Tablelands	Richard Torbay		Independent	Resigned	25 May 2013	Adam Marshall		National
Sydney	Clover Moore		Independent	Resigned due to new state laws preventing dual membership of state parliament and local council	27 October 2012	Alex Greenwich		Independent
Heffron	Kristina Keneally		Labor	Resigned after being appointed CEO of Basketball Australia	25 August 2012	Ron Hoenig		Labor
Clarence	Steve Cansdell		National	Resigned after falsifying a statutory declaration regarding a speeding offence	19 November 2011	Chris Gulaptis		National
Fifty-fourth Legislative Assembly 2007–2011
By-election	Incumbent	Party		Reason	Date	Winner	Party
Penrith	Karyn Paluzzano		Labor	Resigned after misleading ICAC	19 June 2010	Stuart Ayres		Liberal
Ryde	John Watkins		Labor	Resigned to spend time with family	18 October 2008	Victor Dominello		Liberal
Port Macquarie	Rob Oakeshott		Independent	Resigned to contest federal Lyne by-election	18 October 2008	Peter Besseling		Independent
Lakemba	Morris Iemma		Labor	Resigned after losing confidence of caucus	18 October 2008	Robert Furolo		Labor
Cabramatta	Reba Meagher		Labor	Resigned after being dismissed from cabinet	18 October 2008	Nick Lalich		Labor
Fifty-third Legislative Assembly 2003–2007
By-election	Incumbent	Party		Reason	Date	Winner	Party
Pittwater	John Brogden		Liberal	Ill health	26 November 2005	Alex McTaggart		Independent
Macquarie Fields	Craig Knowles		Labor	Resigned after it became apparent that he would not become Premier	17 September 2005	Steven Chaytor		Labor
Maroubra	Bob Carr		Labor	Resigned as Premier	17 September 2005	Michael Daley		Labor
Marrickville	Andrew Refshauge		Labor	Resigned as Deputy Premier	17 September 2005	Carmel Tebbutt		Labor
Dubbo	Tony McGrane		Independent	Death	20 November 2004	Dawn Fardell		Independent
Fifty-second Legislative Assembly 1999–2003
By-election	Incumbent	Party		Reason	Date	Winner	Party
Hornsby	Stephen O'Doherty		Liberal	Resigned	23 February 2002	Judy Hopwood		Liberal
Tamworth	Tony Windsor		Independent	Resigned to contest federal seat of New England at 2001 election	8 December 2001	John Cull		National
Auburn	Peter Nagle		Labor	Ill health	8 September 2001	Barbara Perry		Labor
Campbelltown	Michael Knight		Labor	Resigned after completion of term as Olympics Minister	3 February 2001	Graham West		Labor
Fifty-first Legislative Assembly 1995–1999
By-election	Incumbent	Party		Reason	Date	Winner	Party
Sutherland	Chris Downy		Liberal	Resigned	12 February 1997	Lorna Stone		Liberal
Port Macquarie	Wendy Machin		National	Resigned	30 November 1996	Rob Oakeshott		National
Clarence	Ian Causley		National	Resigned to contest federal seat of Page at the 1996 election	25 May 1996	Harry Woods		Labor
Orange	Garry West		National	Resigned	25 May 1996	Russell Turner		National
Pittwater	Jim Longley		Liberal	Resigned	25 May 1996	John Brogden		Liberal
Southern Highlands	John Fahey		Liberal	Resigned to contest federal seat of Macarthur at the 1996 election	25 May 1996	Peta Seaton		Liberal
Strathfield	Paul Zammit		Liberal	Resigned to contest federal seat of Lowe at the 1996 election	25 May 1996	Bruce MacCarthy		Liberal
Fiftieth Legislative Assembly 1991–1995
By-election	Incumbent	Party		Reason	Date	Winner	Party
Cabramatta	John Newman		Labor	Assassinated by Phuong Ngo	22 October 1994	Reba Meagher		Labor
Parramatta	Andrew Ziolkowski		Labor	Death	27 August 1994	Gabrielle Harrison		Labor
Vaucluse	Michael Yabsley		Liberal	Resigned	9 April 1994	Peter Debnam		Liberal
North Shore	Phillip Smiles		Liberal	Resigned	5 February 1994	Jillian Skinner		Liberal
The Hills	Tony Packard		Liberal	Resigned after involvement in a business scandal	28 August 1993	Michael Richardson		Liberal
Gordon	Tim Moore		Liberal	Resigned (see Metherell affair)	22 August 1992	Jeremy Kinross		Liberal
Ku-ring-gai	Nick Greiner		Liberal	Resigned after losing Premiership (see Metherell affair)	22 August 1992	Stephen O'Doherty		Liberal
Davidson	Terry Metherell		Independent	Accepted an appointment in the public service (see Metherell affair)	2 May 1992	Andrew Humpherson		Liberal
The Entrance	Bob Graham		Liberal	Result overturned by the Court of Disputed Returns	18 January 1992	Grant McBride		Labor
Forty-ninth Legislative Assembly 1988–1991
By-election	Incumbent	Party		Reason	Date	Winner	Party
Coffs Harbour	Matt Singleton		National	Resigned	3 November 1990	Andrew Fraser		National
Macquarie Fields	Stan Knowles		Labor	Resigned	3 November 1990	Craig Knowles		Labor
The Hills	Fred Caterson		Liberal	Resigned	1 September 1990	Tony Packard		Liberal
Granville	Laurie Ferguson		Labor	Successfully contested the federal seat of Reid at the 1990 election	23 June 1990	Kim Yeadon		Labor
Heffron	Laurie Brereton		Labor	Successfully contested the federal seat of Kingsford-Smith at the 1990 election	23 June 1990	Deirdre Grusovin		Labor
Smithfield	Janice Crosio		Labor	Successfully contested the federal seat of Prospect at the 1990 election	23 June 1990	Carl Scully		Labor
Liverpool	George Paciullo		Labor	Resigned after being passed over as leader of the party	29 April 1989	Peter Anderson		Labor
Wallsend	Ken Booth		Labor	Death	17 December 1988	John Mills		Labor
North Shore	Ted Mack		Independent	Resigned	5 November 1988	Robyn Read		Independent
Port Stephens	Bob Martin		Labor	Result voided by the Court of Disputed Returns	5 November 1988	Bob Martin		Labor
Vaucluse	Ray Aston		Liberal	Death	(6 June 1988)*	Michael Yabsley		Liberal
Although the Vaucluse by-election was set for 18 June 1988, Michael Yabsley was declared elected unopposed on the close of nominations on 6 June. Forty-eighth Legislative Assembly 1984–1988
By-election	Incumbent	Party		Reason	Date	Winner	Party
Northern Tablelands	Bill McCarthy		Labor	Resignation due to ill health, dying 3 days later	23 May 1987	Ray Chappell		National
Bankstown	Ric Mochalski		Labor	Resigned after being charged with fraud	31 January 1987	Doug Shedden		Labor
Heathcote	Rex Jackson		Labor	Resigned amidst a corruption scandal that ultimately led to his imprisonment	31 January 1987	Ian McManus		Labor
Rockdale	Brian Bannon		Labor	Accepted a government position and created a seat for the Premier	2 August 1986	Barrie Unsworth		Labor
Bass Hill	Neville Wran		Labor	Resigned	2 August 1986	Michael Owen		Liberal
Pittwater	Max Smith		Independent	Resigned	31 May 1986	Jim Longley		Liberal
Vaucluse	Rosemary Foot		Liberal	Resigned	31 May 1986	Ray Aston		Liberal
Kiama	Bill Knott		Labor	Resigned	1 February 1986	Bob Harrison		Labor
Canterbury	Kevin Stewart		Labor	Accepted position as Agent-General in London	1 February 1986	Kevin Moss		Labor
Cabramatta	Eric Bedford		Labor	Resigned	1 February 1986	John Newman		Labor
Gloucester	Leon Punch		National	Resigned	12 October 1985	Wendy Machin		National
Peats	Paul Landa		Labor	Death	2 February 1985	Tony Doyle		Labor
Murray	Tim Fischer		National	Successfully contested the seat of Farrer at the 1984 federal election	2 February 1985	Jim Small		National
Forty-seventh Legislative Assembly 1981–1984
By-election	Incumbent	Party		Reason	Date	Winner	Party
Maroubra	Bill Haigh		Labor	Resigned after losing cabinet position	22 October 1983	Bob Carr		Labor
Marrickville	Tom Cahill		Labor	Death	22 October 1983	Andrew Refshauge		Labor
Riverstone	Tony Johnson		Labor	Resigned	22 October 1983	Richard Amery		Labor
Kogarah	Bill Crabtree		Labor	Resigned after losing cabinet position	22 October 1983	Brian Langton		Labor
Drummoyne	Michael Maher		Labor	Successfully contested the federal seat of Lowe at the 1982 Lowe by-election	17 April 1982	John Murray		Labor
Forty-sixth Legislative Assembly 1978–1981
By-election	Incumbent	Party		Reason	Date	Winner	Party
Cessnock	Bob Brown		Labor	Successfully contested the federal seat of Hunter at the 1980 election	21 February 1981	Stan Neilly		Labor
Maitland	Milton Morris		Liberal	Unsuccessfully contested the federal seat of Lyne at the 1980 election	21 February 1981	Peter Toms		Liberal
Oxley	Bruce Cowan		National Country	Successfully contested the federal seat of Lyne at the 1980 election	21 February 1981	Peter King		National Country
Sturt	Tim Fischer		National Country	Resigned to successfully contest the seat of Murray at the 1980 Murray by-election	21 February 1981	John Sullivan		National Country
Bankstown	Nick Kearns		Labor	Death	13 September 1980	Ric Mochalski		Labor
Ku-ring-gai	John Maddison		Liberal	Resigned	13 September 1980	Nick Greiner		Liberal
Murray	Mary Meillon		Liberal	Death	13 September 1980	Tim Fischer		National Country
Castlereagh	Jack Renshaw		Labor	Resigned	23 February 1980	Jim Curran		Labor
Forty-fifth Legislative Assembly 1976–1978
By-election	Incumbent	Party		Reason	Date	Winner	Party
Earlwood	Eric Willis		Liberal	Resigned	15 July 1978	Ken Gabb		Labor
The Hills	Max Ruddock		Liberal	Resigned	9 October 1976	Fred Caterson		Liberal
Forty-fourth Legislative Assembly 1973–1976
By-election	Incumbent	Party		Reason	Date	Winner	Party
Orange	Charles Cutler		National Country	Resigned	14 February 1976	Garry West		National Country
Wagga Wagga	Wal Fife		Liberal	Resigned to contest the federal seat of Farrer at the next election	6 December 1975	Joe Schipp		Liberal
Lane Cove	Ken McCaw		Liberal	Resigned	8 February 1975	John Dowd		Liberal
Pittwater	Robert Askin		Liberal	Resigned	8 February 1975	Bruce Webster		Liberal
Coogee	Ross Freeman		Liberal	Result voided by the Court of Disputed Returns	20 July 1974	Michael Cleary		Labor
Goulburn	Ron Brewer		National Country	Unsuccessfully contested the federal seat of Eden-Monaro at the 1974 federal election	20 July 1974	Ron Brewer		National Country
Forty-third Legislative Assembly 1971–1973
By-election	Incumbent	Party		Reason	Date	Winner	Party
Murray	Joe Lawson		Independent	Death	6 October 1973	Mary Meillon		Liberal
Byron	Stanley Stephens		Country	Resigned	17 February 1973	Jack Boyd		Country
Armidale	Davis Hughes		Country	Accepted position as Agent-General in London	17 February 1973	David Leitch		Country
Hawkesbury	Bernie Deane		Liberal	Resigned	17 February 1973	Kevin Rozzoli		Liberal
Charlestown	Jack Stewart		Labor	Death	18 November 1972.	Richard Face		Labor
Mosman	Pat Morton		Liberal	Resigned	29 July 1972	David Arblaster		Liberal
Forty-second Legislative Assembly 1968–1971
By-election	Incumbent	Party		Reason	Date	Winner	Party
Georges River	Douglas Cross		Liberal	Death	19 September 1970	Frank Walker		Labor
Murrumbidgee	Al Grassby		Labor	Successfully contested the federal seat of Riverina at the 1969 federal election	14 February 1970	Lin Gordon		Labor
Randwick	Lionel Bowen		Labor	Successfully contested the federal seat of Kingsford Smith at the 1969 federal election	14 February 1970	Laurie Brereton		Labor
Upper Hunter	Frank O'Keefe		Country	Successfully contested the federal seat of Paterson at the 1969 federal election	14 February 1970	Col Fisher		Country
Lake Macquarie	Jim Simpson		Labor	Death	9 April 1969	Merv Hunter		Labor
Forty-first Legislative Assembly 1965–1968
By-election	Incumbent	Party		Reason	Date	Winner	Party
Bathurst	Gus Kelly		Labor	Death	6 May 1967	Clive Osborne		Country
Oxley	Les Jordan		Liberal	Death	6 November 1965	Bruce Cowan		Country
Bondi	Abe Landa		Labor	Accepted the position of state Agent-General in London	6 November 1965	Syd Einfeld		Labor
Fortieth Legislative Assembly 1962–1965
By-election	Incumbent	Party		Reason	Date	Winner	Party
Lakemba	Stan Wyatt		Labor	Death	19 September 1964	Vince Durick		Labor
Waratah	Edward Greaves		Labor	Death	8 August 1964	Frank Purdue		Independent
Wollongong-Kembla	Rex Connor		Labor	Successfully contested the federal seat of Cunningham at the 1963 election	29 February 1964	Doug Porter		Labor
Casino	Ian Robinson		Country	Successfully contested the federal seat of Cowper at the 1963 election	29 February 1964	Richmond Manyweathers		Country
Thirty-ninth Legislative Assembly 1959–1962
By-election	Incumbent	Party		Reason	Date	Winner	Party
Liverpool Plains	Roger Nott		Labor	Accepted an appointment as Administrator of the Northern Territory	25 March 1961	Frank O'Keefe		Country
Paddington-Waverley	William Ferguson		Labor	Death	25 February 1961	Keith Anderson		Labor
Temora	Doug Dickson		Country	Death	8 October 1960	Jim Taylor		Country
Kurri Kurri	George Booth		Labor	Death	8 October 1960	Ken Booth		Labor
Cook's River	Joseph Cahill		Labor	Death	12 December 1959	Tom Cahill		Labor
Lismore	Jack Easter		Country	Result voided by the Court of Disputed Returns	12 September 1959.	Keith Compton		Labor
Thirty-eighth Legislative Assembly 1956–1959
By-election	Incumbent	Party		Reason	Date	Winner	Party
Wagga Wagga	Eddie Graham		Labor	Death	14 December 1957	Wal Fife		Liberal
Wollondilly	Blake Pelly		Liberal	Resigned	26 October 1957	Tom Lewis		Liberal
Vaucluse	Murray Robson		Liberal	Resigned	24 August 1957	Geoffrey Cox		Liberal
Kahibah	Tom Armstrong		Independent Labor	Death	13 April 1957	Jack Stewart		Labor
Burwood	Leslie Parr		Liberal	Death	16 February 1957	Ben Doig		Liberal
Thirty-seventh Legislative Assembly 1953–1956
By-election	Incumbent	Party		Reason	Date	Winner	Party
Bulli	Laurie Kelly Sr.		Labor	Death	9 July 1955	Rex Jackson		Labor
Clarence	Cecil Wingfield		Country	Death	26 March 1955	Bill Weiley		Country
Phillip	Tom Shannon		Labor	Death	14 August 1954	Pat Hills		Labor
Leichhardt	Claude Matthews		Labor	Committed suicide	20 March 1954	Reg Coady		Labor
Kahibah	Joshua Arthur		Labor	Resigned after being expelled from the Labor Party, following adverse findings into his conduct by a Royal Commission	31 October 1953	Tom Armstrong		Independent Labor
Waverley	Clarrie Martin		Labor	Death	31 October 1953	William Ferguson		Labor
Dulwich Hill	George Weir		Labor	Appointed to the Industrial Relations Commission of New South Wales	20 June 1953	Cliff Mallam		Labor
Thirty-sixth Legislative Assembly 1950–1953
By-election	Incumbent	Party		Reason	Date	Winner	Party
Ashfield	Athol Richardson		Liberal	Accepted an appointment as a Judge of the Supreme Court	28 June 1952	Jack Richardson		Labor
Liverpool	James McGirr		Labor	Appointed chair of the Maritime Services Board	24 May 1952	Jack Mannix		Labor
Neutral Bay	Ivan Black		Liberal	Unsuccessfully contested preselection for the federal seat of Warringah at the 1951 election	(21 May 1951)	Ivan Black		Liberal
Burwood	Gordon Jackett		Liberal	Death	2 June 1951	Leslie Parr		Liberal
Thirty-fifth Legislative Assembly 1947–1950
By-election	Incumbent	Party		Reason	Date	Winner	Party
Concord	Brice Mutton		Liberal	Death	11 February 1950	John Adamson		Liberal
Wollongong-Kembla	Billy Davies		Labor	Successfully contested the seat of Cunningham at the 1949 federal election	11 February 1950	Baden Powell		Labor
Armidale	David Drummond		Country	Successfully contested the seat of New England at the 1949 federal election	11 February 1950	Davis Hughes		Country
Wollondilly	Jeff Bate		Liberal	Successfully contested the seat of Macarthur at the 1949 federal election	(23 January 1950)	Blake Pelly		Liberal
Cessnock	Jack Baddeley		Labor	Accepted an appointment as Chairman of the State Coal Mine Authority	8 October 1949	John Crook		Labor
Redfern	George Noble		Labor	Death	8 October 1949	Kevin Dwyer		Labor
Concord	Bill Carlton		Labor	Death	12 March 1949	Brice Mutton		Liberal
Cobar	Mat Davidson		Labor	Death	12 March 1949	Ernest Wetherell		Labor
Kogarah	William Currey		Labor	Death	17 July 1948	Douglas Cross		Liberal
Coogee	Lou Cunningham		Labor	Death	8 May 1948	Kevin Ellis		Liberal
Hartley	Hamilton Knight		Labor	Accepted an appointment to the Commonwealth Industrial Commission	13 December 1947	Jim Chalmers		Labor
Thirty-fourth Legislative Assembly 1944–1947
By-election	Incumbent	Party		Reason	Date	Winner	Party
Corowa	Christopher Lethbridge		Liberal	Unsuccessfully contested the federal seat of Riverina at the 1946 federal election	9 November 1946	Ebenezer Kendell		Country
Ashfield	Athol Richardson		Liberal	Unsuccessfully contested the federal seat of Parkes at the 1946 federal election	9 November 1946	Athol Richardson		Liberal
Auburn	Jack Lang		Lang Labor	Successfully contested the federal seat of Reid at the 1946 federal election	9 November 1946	Chris Lang		Lang Labor
Albury	Alexander Mair		Liberal	Unsuccessfully contested a seat in the Australian Senate at the 1946 federal election	9 November 1946	John Hurley		Labor
Goulburn	Jack Tully		Labor	Resigned	1 June 1946	Laurie Tully		Labor
Neutral Bay	Reginald Weaver		Liberal	Death	15 December 1945	Ivan Black		Liberal
Manly	Alfred Reid		Liberal	Death	15 September 1945	Douglas Darby		Liberal
Blacktown	Frank Hill		Labor	Death	18 August 1945	John Freeman		Labor
Ryde	James Shand		Independent Democrat	Death	3 February 1945	Eric Hearnshaw		Liberal
Thirty-third Legislative Assembly 1941–1944
By-election	Incumbent	Party		Reason	Date	Winner	Party
Auburn	Jack Lang		Lang Labor	Unsuccessfully contested the federal seat of Reid at the 1943 election	2 October 1943	Jack Lang		Lang Labor
Lachlan	Griffith Evans		Country	Death	25 September 1943	John Chanter		Labor
Willoughby	Edward Sanders		UAP	Death	25 September 1943	George Brain		UAP
South Coast	Rupert Beale		Independent	Death	14 November 1942	Jack Beale		Independent
Dubbo	George Wilson		Country	Death	6 June 1942	Clarrie Robertson		Labor
Thirty-second Legislative Assembly 1938–1941
By-election	Incumbent	Party		Reason	Date	Winner	Party
Barwon	Ben Wade		Country	Unsuccessfully contest the federal seat of Gwydir at the 1940 election	16 November 1940	Roy Heferen		Labor
Ryde	Eric Spooner		UAP	Successfully contested the federal seat of Robertson at the 1940 election	14 September 1940	Arthur Williams		Labor
Croydon	Bertram Stevens		UAP	Unsuccessfully contested the federal seat of Lang at the 1940 election	7 September 1940	David Hunter		UAP
Tamworth	Frank Chaffey		UAP	Death	10 August 1940	Bill Chaffey		UAP
Upper Hunter	Malcolm Brown		Country	Death	7 October 1939	D'Arcy Rose		Country
Waverley	John Waddell		UAP	Death	22 April 1939	Clarrie Martin		Industrial Labor
Hurstville	James Webb		UAP	Death	18 March 1939	Clive Evatt		Industrial Labor
Balmain	John Quirk		Labor	Death	14 January 1939	Mary Quirk		Labor
Wollondilly	Mark Morton		UAP	Death	12 November 1938	Jeff Bate		UAP
Gordon	Harry Turner		UAP	Result voided by Court of Disputed Returns	24 September 1938	Harry Turner		UAP
Coogee	John Dunningham		UAP	Death	25 June 1938	Thomas Mutch		UAP
Thirty-first Legislative Assembly 1935–1938
By-election	Incumbent	Party		Reason	Date	Winner	Party
Corowa	Richard Ball		Country	Death	11 December 1937	Christopher Lethbridge		Independent
Gordon	Philip Goldfinch		UAP	Resigned (Increased commitment to business interests)	7 August 1937	Harry Turner		UAP
Woollahra	Daniel Levy		UAP	Death	26 June 1937	Harold Mason		Independent UAP
Vaucluse	William Foster		UAP	Death	29 August 1936	Murray Robson		Independent UAP
Gordon	Thomas Bavin		UAP	Accepted an appointment as a Judge of the Supreme Court	(23 November 1935)	Philip Goldfinch		UAP
Thirtieth Legislative Assembly 1932–1935
By-election	Incumbent	Party		Reason	Date	Winner	Party
Leichhardt	Joe Lamaro		Labor (NSW)	Unsuccessfully contested the federal seat of Watson at the 1934 election	20 October 1934	Claude Matthews		Labor (NSW)
Gloucester	Walter Bennett		UAP	Death	25 August 1934	Charles Bennett		UAP
Hamilton	Hugh Connell		Labor (NSW)	Death	24 February 1934	William Brennan		Labor (NSW)
Annandale	Robert Stuart-Robertson		Labor (NSW)	Death	24 June 1933	Bob Gorman		Labor (NSW)
Bulli	Andrew Lysaght, junior		Labor (NSW)	Death	3 June 1933	John Sweeney		Labor (NSW)
Lismore	William Missingham		Country	Death	11 March 1933	William Frith		Country
Leichhardt	Barney Olde		Labor (NSW)	Death	10 December 1932	Joe Lamaro		Labor (NSW)
Twenty-ninth Legislative Assembly 1930–1932
By-election	Incumbent	Party		Reason	Date	Winner	Party
Upper Hunter	William Cameron		Nationalist	Death	13 June 1931	Malcolm Brown		Independent Country
Annandale	Robert Stuart-Robertson		Labor (NSW)	Insolvency	25 April 1931	Robert Stuart-Robertson		Labor (NSW)
Clarence	Alfred Pollack		Country	Death	7 March 1931	Alfred Henry		Country
Twenty-eighth Legislative Assembly 1927–1930
By-election	Incumbent	Party		Reason	Date	Winner	Party
Lane Cove	Bryce Walmsley		Nationalist	Death	26 July 1930	Herbert FitzSimons		Nationalist
Ashfield	Milton Jarvie		Nationalist	Resigned after being implicated in a bribery scandal	5 October 1929	Milton Jarvie		Nationalist
Parramatta	Albert Bruntnell		Nationalist	Death	23 February 1929	Herbert Lloyd		Nationalist
Coogee	Hyman Goldstein		Nationalist	Death – probably murdered by ex-MLA Tom Ley	22 September 1928	John Dunningham		Nationalist
Hamilton	David Murray		Labor	Death	8 September 1928	James Smith		Labor
Wollondilly	George Fuller		Nationalist	Accepted position as Agent-General in London in February 1928	3 March 1928	Mark Morton		Nationalist
Twenty-seventh Legislative Assembly 1925–1927 The 25th, 26th and 27th Legislative Assemblies were elected using a form of proportional representation with multi-member seats and a single transferable vote (modified Hare-Clark). Under the provisions of the Parliamentary Elections (Casual Vacancies) Act, casual vacancies were filled by the next unsuccessful candidate on the incumbent member's party list. If an Independent member retired, the Clerk of the Assembly determined who would fill the vacancy based on the departing members voting record in questions of confidence. The date listed as the by-election date is the day on which the new member was sworn into the Assembly.
Electorate	Incumbent	Party		Reason for vacancy	Date of appointment	Person appointed	Party
Cumberland	William FitzSimons		Nationalist	Death	(22 September 1926)	James Shand		Nationalist
North Shore	Alick Kay ¶		Independent	Accepted a position on the Metropolitan Meat Board.	(22 September 1926)	Arthur Tonge		Labor
Goulburn	John Perkins		Nationalist	Resigned to successfully contest the federal seat of Eden-Monaro at the 1926 Eden-Monaro by-election.	(21 January 1926)	Henry Bate		Nationalist
St George	Thomas Ley		Nationalist	Resigned to successfully contest the federal seat of Barton at the 1925 election	(30 September 1925)	William Bagnall		Nationalist
Sydney	John Birt		Labor	Death	(24 June 1925)	Patrick Minahan		Labor
¶ Kay had supported the Lang Government in votes of confidence in the Assembly, the Clerk of the Parliament therefore named the first unsuccessful Labor candidate in the North Shore electorate as his replacement. Twenty-sixth Legislative Assembly 1922–1925
Electorate	Incumbent	Party		Reason for vacancy	Date of appointment	Person appointed	Party
North Shore	Arthur Cocks		Nationalist	Accepted position of Agent-General in London	(24 March 1925)	Alfred Reid		Nationalist
Namoi	Patrick Scully		Labor	Resigned	(20 September 1923)	William Scully		Labor
Sturt	Jabez Wright		Labor	Death	(30 September 1922)	Ted Horsington		Labor
Wammerawa	William Ashford		Independent	Result overturned (Change of member without by-election)	(26 July 1922)	Joseph Clark		Labor
Twenty-fifth Legislative Assembly 1920–1922
Electorate	Incumbent	Party		Reason for vacancy	Date of appointment	Person appointed	Party
Goulburn ‡	William Millard		Nationalist	Death	(22 November 1921)	John Perkins		Nationalist
Balmain	John Storey		Labor	Death	(18 October 1921)	Tom Keegan		Labor
Newcastle	William Kearsley		Labor	Death	(30 August 1921)	David Murray		Labor
Sturt ¶	Percy Brookfield		Socialist Labor	Murdered while trying to disarm a deranged man at Riverton	(30 August 1921)	Jabez Wright		Labor
Oxley	George Briner		Progressive	Death	(15 December 1920)	Theodore Hill		Progressive
Eastern Suburbs	James Fingleton		Labor	Death	(15 December 1920)	Daniel Dwyer		Labor
Goulburn	Gus James		Nationalist	Accepted an appointment as a Judge of the Supreme Court	(15 December 1920)	William Millard		Nationalist
Murray	George Beeby		Progressive	Accepted a judicial appointment	(15 December 1920)	Matthew Kilpatrick		Progressive
¶ The Speaker had received correspondence nominating two unsuccessful candidates from the 1920 election, Thomas Hynes and John O'Reilly. However, the terms of the Parliamentary Elections (Casual Vacancies) Act stated that a nomination to fill the vacancy had to come from a recognised party leader. Labor leader and Premier John Storey nominated Jabez Wright. ‡Millard had been appointed to replace Gus James and, as there were no further unsuccessful Nationalist candidates, the Parliamentary Elections (Casual Vacancies) Act was amended to allow his replacement by another Nationalist supporter. Twenty-fourth Legislative Assembly 1917–1920
By-election	Incumbent	Party		Reason	Date	Winner	Party
Paddington	Lawrence O'Hara		Labor	Death	26 July 1919	John Birt		Labor
Paddington	John Osborne		Labor	Accepted as appointment to the Metropolitan Meat Board	24 May 1919	Lawrence O'Hara		Labor
Petersham	John Cohen		Nationalist	Accepted an appointment as a Judge of the District Court	22 March 1919	Sydney Shillington		Nationalist
Monaro	Gus Miller		Labor	Death	23 November 1918	John Bailey		Labor
Upper Hunter	Mac Abbott		Nationalist	Resigned	8 June 1918	William Cameron		Nationalist
Cobar	Charles Fern		Labor	Death	(1 June 1918)	Mat Davidson		Labor
Gloucester	Richard Price		Independent Liberal	Expelled after a Royal Commission found he had made "wanton lies" in an attack on the Lands Minister William Ashford	10 November 1917	Richard Price		Independent Liberal
Murray	Robert Scobie		Nationalist	Death	22 September 1917	Brian Doe		Nationalist
Macquarie	Thomas Thrower		Labor	Death	12 July 1917	Patrick McGirr		Labor
Twenty-third Legislative Assembly 1913–1917
By-election	Incumbent	Party		Reason	Date	Winner	Party
Sturt	John Cann		Labor	Accepted the position of Commissioner of Railways	3 February 1917	Percy Brookfield		Labor
Bingara	George McDonald		Labor	Resigned from Labor after the 1916 NSW Labor Conference passed a motion of no confidence in the Holman government	10 June 1916	George McDonald		Independent Labor
Parramatta	Tom Moxham		Liberal Reform	Death	12 February 1916	Albert Bruntnell		Liberal Reform
Drummoyne	George Richards		Liberal Reform	Death	22 January 1916	Alexander Graff		Liberal Reform
Willoughby	Edward Larkin		Labor	Died on active service on 25 April 1915	25 September 1915	John Haynes		Independent
Wollondilly	Frank Badgery		Liberal Reform	Death	(2 October 1915)	George Fuller		Liberal Reform
Armidale	George Braund		Liberal Reform	Died on active service	(18 September 1915)	Herbert Lane		Liberal Reform
Clarence	John McFarlane		Liberal Reform	Death	14 August 1915	William Zuill		Farmers and Settlers
Castlereagh	John Treflé		Labor	Death	20 February 1915	Guy Arkins		Labor
Canterbury	Henry Peters		Labor	Bankrupt	10 October 1914	George Cann		Labor
Twenty-second Legislative Assembly 1910–1913
By-election	Incumbent	Party		Reason	Date	Winner	Party
Wollondilly	William McCourt		Liberal Reform	Death	19 July 1913	Frank Badgery		Liberal Reform
Blayney	George Beeby		Labor	Resigned from the ministry, parliament and party in protest at the power of the extra-parliamentary Labor Party executive	23 January 1913	George Beeby		Independent
Alexandria	John Dacey		Labor	Death	18 May 1912	Simon Hickey		Labor
Maitland	John Gillies		Independent Liberal	Death	28 October 1911	Charles Edward Nicholson		Liberal Reform
Yass	Niels Nielson		Labor	¶	5 March 1913	Greg McGirr		Labor
Cobar	Donald Macdonell		Labor	¶	(16 December 1911)	Charles Fern		Labor
Cobar	Donald Macdonell		Labor	¶	(7 October 1911)	Donald Macdonell		Labor
Liverpool Plains	John Perry		Liberal Reform	¶	28 October 1911	William Ashford		Labor
Liverpool Plains	Henry Hoyle		Labor	¶	16 August 1911	John Perry		Liberal Reform
Mudgee	Bill Dunn		Labor	¶	16 August 1911	Bill Dunn		Labor
¶ Mudgee Labor MLA Bill Dunn and Liverpool Plains Labor MLA Henry Hoyle resigned from the Labor Party and Parliament on 25 July 1911 in protest at legislation on land ownership introduced by Lands Minister, Niels Nielson. As a result, Labor was left without a majority in the house and rather than face a vote of no confidence, the Ministry and Speaker resigned. This forced the House to be prorogued with the result that Cobar Labor MLA, Donald Macdonell, who was unwell but expected to recover, was automatically expelled for non-attendance during an entire session. By the time of the subsequent by-elections, Labor policy had been reversed and Nielsen had left the ministry. Dunn rejoined the party and successfully re-contested, the Mudgee by-election on 16 August 1911. Hoyle did not re-contest the Liverpool Plains by-election which was won by Liberal candidate, John Perry by three votes on the same day. This result was overturned on appeal and at the second by-election on 28 October, Labor candidate, William Ashford was successful. In Cobar, Macdonell was unopposed when re-elected on 7 October, but died three weeks later. The Labor candidate, Charles Fern was unopposed at the second by-election on 16 December. Denied further ministerial appointment Nielsen resigned from the seat of Yass and Labor candidate Greg McGirr won the resultant by-election on 19 July 1913. Twenty-first Legislative Assembly 1907–1910
By-election	Incumbent	Party		Reason	Date	Winner	Party
Belmore	Edward O'Sullivan		Labor	Death	21 May 1910	Patrick Minahan		Labor
Darling Harbour	John Norton		Independent	Resigned to unsuccessfully contest a Senate seat at the 1910 election	13 April 1910	John Cochran		Labor
Queanbeyan	Granville Ryrie		Liberal Reform	Resigned to unsuccessfully contest the federal seat of Werriwa at the 1910 election	13 April 1910	John Cusack		Labor
Upper Hunter	William Fleming		Liberal Reform	Resigned to unsuccessfully contest the federal seat of New England at the 1910 election	13 April 1910	William Ashford		Labor
Northumberland	Matthew Charlton		Labor	Resigned to successfully contest the federal seat of Hunter at the 1910 election	(23 March 1910)	William Kearsley		Labor
Sturt	Arthur Griffith		Labor	Resigned from parliament after a dispute with the Speaker	(21 November 1908)	Arthur Griffith		Labor
St George	Joseph Carruthers		Liberal Reform	Resigned	20 May 1908	William Taylor		Liberal Reform
Twentieth Legislative Assembly 1904–1907
By-election	Incumbent	Party		Reason	Date	Winner	Party
Blayney	Paddy Crick		Progressive	Resigned after being acquitted of corruption charges	12 January 1907	John Withington		Liberal Reform
Castlereagh	Hugh Macdonald		Labor	Death	24 November 1906	John Treflé		Labor
Surry Hills	John Norton		Independent	Challenged William Holman to face a by-election	21 July 1906	Albert Bruntnell		Liberal Reform
Cootamundra	William Holman		Labor	Challenged to a by-election by John Norton	17 July 1906	William Holman		Labor
Queanbeyan	Alan Millard		Liberal Reform	Criminal conviction: Fraud	7 April 1906	Granville Ryrie		Liberal Reform
Ashfield	Frederick Winchcombe		Liberal Reform	Extended absence visiting England	16 August 1905	William Robson		Liberal Reform
Rous	John Coleman		Liberal Reform	Death	11 February 1905	George Hindmarsh		Liberal Reform
Nineteenth Legislative Assembly 1901–1904
By-election	Incumbent	Party		Reason	Date	Winner	Party
Ryde	Frank Farnell		Independent Liberal	Appointment to Fisheries Board	23 January 1904	Edward Terry		Independent Liberal
Illawarra	Archibald Campbell		Liberal Reform	Death	9 January 1904	Edward Allen		Liberal Reform
Moree	William Webster		Labor	Successful candidate for Gwydir at federal election	12 December 1903	Percy Stirton		Liberal Reform
Armidale	Edmund Lonsdale		Liberal Reform	Successful candidate for New England at federal election	12 December 1903	Sydney Kearney		Liberal Reform
Waratah	Arthur Griffith		Labor	Unsuccessful candidate for Senate at federal election	5 December 1903	Matthew Charlton		Labor
Glen Innes	Francis Wright		Progressive	Death	28 October 1903	Follett Thomas		Liberal Reform
Willoughby	George Howarth		Liberal Reform	Bankruptcy	9 September 1903	Charles Wade		Liberal Reform
Tamworth	Raymond Walsh		Progressive	Bankruptcy	4 April 1903	John Garland		Liberal Reform
Balmain South	Sydney Law		Labor	Refused Caucus solidarity pledge	6 December 1902	Sydney Law		Independent Labor
Inverell	William McIntyre		Progressive	Death	31 May 1902	George Jones		Labor
Sydney-Pyrmont	Samuel Smith		Labor	Appointment to Court of Arbitration	24 May 1902	John McNeill		Labor
Condoublin	Patrick Clara		Labor	Election overturned by the Elections and Qualifications Committee	4 November 1901	Patrick Clara		Labor
Eighteenth Legislative Assembly 1898–1901
By-election	Incumbent	Party		Reason	Date	Winner	Party
Hume	William Lyne		Protectionist	Successfully contested Hume at 1901 Federal election	17 April 1901	Gordon McLaurin		Protectionist
Ashfield	Bernhard Wise		Protectionist	Appointed to Legislative Council	10 November 1900	Frederick Winchcombe		Free Trade
Uralla-Walcha	William Piddington		Protectionist	Death	27 October 1900	Michael MacMahon		Protectionist
Bourke	William Davis		Protectionist	Resignation due to insolvency	(6 September 1900)	William Davis		Protectionist
Canterbury	Sydney Smith		Free Trade	By-election result voided by the Elections and Qualifications Committee	28 July 1900	Thomas Taylor		Independent
Bathurst	Francis Suttor		Protectionist	Appointed to Legislative Council	25 June 1900	William Young		Protectionist
Canterbury	Varney Parkes		Free Trade	Resignation	9 June 1900	Sydney Smith		Free Trade
Uralla-Walcha	William Piddington		Protectionist	Resignation due to insolvency	9 June 1900	William Piddington		Protectionist
Sydney-Phillip	Henry Copeland		Protectionist	Accepted post as Agent-General in London	7 April 1900	Daniel O'Connor		Protectionist
Hastings and Macleay	Edmund Barton		Protectionist	Resigned to take Constitution to London	1 March 1900	Francis Clarke		Protectionist
Boorowa	Kenneth Mackay		Protectionist	Appointed to Legislative Council	30 September 1899	Niels Nielsen		Labor
Northumberland	Richard Stevenson		National Federal	Death	20 July 1899	John Norton		Independent
Parramatta	William Ferris		Independent Federalist	Election declared void by the Elections and Qualifications Committee	26 October 1898	William Ferris		Protectionist
Hastings and Macleay	Francis Clarke		National Federal	Resigned to give Barton a seat	23 September 1898	Edmund Barton		National Federal
Seventeenth Legislative Assembly 1895–1898
By-election	Incumbent	Party		Reason	Date	Winner	Party
Sydney-Fitzroy	John McElhone		Independent Free Trade	Death	3 June 1898	John Norton		Protectionist
Narrabri	Charles Collins		Free Trade	Death	3 June 1898	Hugh Ross		Labor
Lachlan	James Carroll		Protectionist	Resignation due to insolvency	(11 September 1896)	James Carroll		Protectionist
Cowra	Denis Donnelly		Protectionist	Death	27 March 1896	Michael Phillips		Protectionist
Waverley	Angus Cameron		Free Trade	Death	18 February 1896	Thomas Jessep		Free Trade
Sydney-Phillip	Dick Meagher		Protectionist	Resigned in disgrace in relation to the pardon of George Dean	17 October 1895	Henry Copeland		Protectionist
Rylstone	John Fitzpatrick		Free Trade	Election result voided by the Elections and Qualifications Committee	14 October 1895	John Fitzpatrick		Free Trade
Sixteenth Legislative Assembly 1894–1895
By-election	Incumbent	Party		Reason	Date	Winner	Party
Canterbury	Varney Parkes		Free Trade	Resignation due to insolvency	(14 June 1895)	Varney Parkes		Free Trade
Bowral	William McCourt		Free Trade	Resignation due to insolvency	(19 February 1895)	William McCourt		Free Trade
Boorowa	Thomas Slattery		Protectionist	Resigned	15 January 1895	Kenneth Mackay		Protectionist
Willoughby	Joseph Cullen		Free Trade	Resignation due to insolvency	30 November 1894	Edward Clark		Free Trade
Tweed	John Willard		Labor	Not a resident of NSW	29 November 1894	Joseph Kelly		Protectionist
Grenfell	George Greene		Free Trade	Election result overturned by the Elections and Qualifications Committee (no by-election)	(25 October 1894)	Michael Loughnane		Labor
Fifteenth Legislative Assembly 1891–1894
By-election	Incumbent	Party		Reason	Date	Winner	Party
Macleay	Otho Dangar		Protectionist	Financial difficulty	29 May 1893	Francis Clarke		Protectionist
Central Cumberland	John Nobbs		Free Trade	Financial difficulty	6 May 1893	George McCredie		Free Trade
Murrumbidgee	George Dibbs		Protectionist	Financial difficulty	(6 April 1893)	George Dibbs		Protectionist
South Sydney	James Toohey		Protectionist	Resigned	13 February 1893	William Manning		Protectionist
East Macquarie	James Tonkin		Free Trade	Financial difficulty	13 August 1892	James Tonkin		Free Trade
Hawkesbury	Alexander Bowman		Free Trade	Death	23 July 1892	Sydney Burdekin		Free Trade
Bogan	George Cass		Protectionist	Death	31 May 1892	William A'Beckett		Free Trade
Bourke	Peter Howe		Protectionist	Resigned after conviction for conspiracy to defraud	4 December 1891	Thomas Waddell		Protectionist
Illawarra	John Nicholson		Labor	Previous result voided by the Elections and Qualifications Committee	3 October 1891	John Nicholson		Labor
	Andrew Lysaght		Protectionist			Archibald Campbell		Free Trade
Canterbury	John Wheeler		Free Trade	Election result overturned by the Elections and Qualifications Committee (no by-election)	(2 September 1891)	James Eve		Free Trade
Central Cumberland	Robert Ritchie		Free Trade	Death	29 August 1891	Jacob Garrard		Free Trade
Fourteenth Legislative Assembly 1889–1891
By-election	Incumbent	Party		Reason	Date	Winner	Party
Wellington	David Ferguson		Protectionist	Death	29 May 1891	Thomas York		Protectionist
East Sydney	John Street		Free Trade	Death	14 April 1891	Walter Bradley		Protectionist
Newcastle	James Fletcher		Protectionist	Death	14 April 1891	William Grahame		Protectionist
West Macquarie	Paddy Crick		Protectionist	Expelled for outrageous behaviour in the chamber	6 December 1890	Paddy Crick		Protectionist
West Sydney	Alfred Lamb		Free Trade	Death	25 October 1890	Adolphus Taylor		Independent
Goulburn	William Teece Jr		Free Trade	Death	16 August 1890	Cecil Teece		Free Trade
Namoi	Tom Dangar		Free Trade	Death	31 July 1890	Charles Collins		Free Trade
Hartley	John Hurley		Free Trade	Financial Difficulty	22 July 1890	John Hurley		Free Trade
Balmain	John Hawthorne		Free Trade	Financial Difficulty	(10 July 1890)	John Hawthorne		Free Trade
Hastings and Manning	Charles Roberts		Free Trade	Resigned	5 April 1890	Walter Vivian		Free Trade
Monaro	Harold Stephen		Protectionist	Death	17 December 1889	Gus Miller		Protectionist
Newcastle	William Grahame		Protectionist	Financial Difficulty	12 October 1889	James Curley		Free Trade
Central Cumberland	Frank Farnell		Free Trade	Financial difficulty	(5 October 1889)	Frank Farnell		Free Trade
Central Cumberland	John Linsley		Free Trade	Death	22 July 1889	David Dale		Free Trade
Redfern	John Sutherland		Protectionist	Death	8 July 1889	William Schey		Protectionist
Tamworth	Robert Levien		Protectionist	Sought a new mandate after being involved in a legal scandal	(18 June 1889)	Robert Levien		Protectionist
Thirteenth Legislative Assembly 1887–1889
By-election	Incumbent	Party		Reason	Date	Winner	Party
Gunnedah	Thomas Goodwin		Protectionist	Resigned	12 September 1888	Edwin Turner		Free Trade
Redfern	James Farnell		Free Trade	Death	8 September 1888	Peter Howe		Protectionist
Central Cumberland	Andrew McCulloch		Free Trade	Financial difficulty	15 May 1888	David Buchanan		Protectionist
Central Cumberland	Varney Parkes		Free Trade	Business commitments	14 March 1888	John Nobbs		Free Trade
Newtown	William Foster		Free Trade	Accepted an appointment as a Judge of the Supreme Court	25 February 1888	Joseph Mitchell		Free Trade
Newtown	Frederick Gibbes		Free Trade	Death	3 February 1888	Joseph Abbott		Free Trade
Paddington	William Trickett		Free Trade	Appointed to Legislative Council	12 January 1888	William Allen		Protectionist
Central Cumberland	Andrew McCulloch		Free Trade	Financial difficulty	28 December 1887	Andrew McCulloch		Free Trade
St Leonards	Henry Parkes		Free Trade	Financial difficulty	(25 October 1887)	Henry Parkes		Free Trade
Wentworth	William MacGregor		Independent Free Trade	Resigned	28 September 1887	Thomas Browne		Protectionist
Mudgee	Adolphus Taylor		Free Trade	Accepted position as Examiner of Patents	11 May 1887	John Haynes		Free Trade

No party system was discernible in the New South Wales parliament before the election of 1887

Twelfth Legislative Assembly 1885–1887
By-election	Incumbent	Reason	Date	Winner
Bourke	Russell Barton William Sawers	Resigned	21 January 1887	Parliament dissolved before writ returned
Kiama	Harman Tarrant	Resigned	13 January 1887	Angus Cameron
New England	William Proctor	Resigned	10 January 1887	William Proctor
Yass Plains	Louis Heydon	Retired	20 December 1886	Thomas Colls
Wollombi	Lyall Scott	Retired (ill-health)	17 December 1886	Richard Stevenson
Mudgee	John Robertson	Retired (ill-health, financial difficulties and loss of premiership)	(2 July 1886)	William Wall
Gwydir	William Campbell	Resigned	10 June 1886	Thomas Hassall
Young	William Watson	Election result overturned by the Qualifications Committee (no by-election)	(22 December 1885)	James MacKinnon
Eleventh Legislative Assembly 1882–1885
By-election	Incumbent	Reason	Date	Winner
Central Cumberland	John Lackey	Accepted nomination to the Legislative Council	24 September 1885	Varney Parkes.
Canterbury	Henry Moses	Accepted nomination to the Legislative Council	16 September 1885	William Henson
St Leonards	Bernhardt Holtermann	Death	4 June 1885	Isaac Ives
Argyle	John Gannon	Resigned due to ill health	31 March 1885	Henry Parkes
Carcoar	Andrew Lynch	Death	21 November 1884	Ezekial Baker
Tenterfield	Henry Parkes	Resigned, claiming that he was retiring from politics	(24 November 1884)	Charles Lee
Monaro	Robert Tooth	Resigned	(24 July 1884)	David Ryrie
West Macquarie	Thomas Hellyer	Resigned	2 July 1884	Lewis Lloyd
Northumberland	Atkinson Tighe	Resigned due to ill health	26 May 1884	Richard Luscombe
Gundagai	Bruce Smith	Resigned	22 April 1884	James Watson
Canterbury	William Pigott	Resigned (private work commitments)	19 April 1884	Mark Hammond
East Sydney	George Reid	Found to have a position of profit under the crown	29 February 1884	Sydney Burdekin
Bathurst	Francis Suttor	Found to have a position of profit under the crown	(11 February 1884)	Francis Suttor
Glebe	George Allen	Prolonged voyage to England.	26 August 1883	Michael Chapman
Upper Hunter	John McElhone	Challenged Adolphus Taylor to resign	6 March 1883	John McElhone
Mudgee	Adolphus Taylor	Challenged by John McElhone to resign	6 March 1883	Adolphus Taylor
East Sydney	John McElhone	Elected to two seats	23 January 1883	Henry Copeland
Newtown	Henry Copeland	Ministerial (defeated)	13 January 1883	Joseph Mitchell
Tenth Legislative Assembly 1880–1882
By-election	Incumbent	Reason	Date	Winner
Gundagai	William Forster	Death	23 November 1882	Bruce Smith
Tumut	James Hoskins	Resigned to take a recuperative sea voyage	17 October 1882	Thomas O'Mara
East Macquarie	Alfred Pechey	Death	11 July 1882	Sydney Smith
Tenterfield	John Dillon	Resigned	6 February 1882	Augustus Fraser
Wentworth	William Brodribb	Appointed to the Legislative Council	23 January 1882	Edward Quin
East Macquarie	Edmund Webb	Appointed to the Legislative Council	19 January 1882	Alfred Pechey
Northumberland	William Turner	Resigned (He was supported by the local coal miners union, however the subscriptions were insufficient to support him in the assembly)	18 January 1882	Thomas Hungerford
Mudgee	Samuel Terry	Appointed to the Legislative Council	(20 January 1882)	John Robertson
Redfern	John Sutherland	Appointed to the Legislative Council	11 January 1882	Francis Wright
Yass Plains	Michael Fitzpatrick	Death	10 January 1882	Louis Heydon
Argyle	Phillip G. Myers	Death	9 December 1881	John Gannon
Newtown	Stephen Brown	Appointed to the Legislative Council	1 December 1881	Joseph Mitchell
Carcoar	Ezekial Baker	Expelled after he had been found to have fraudulently dealt with trust funds	1 December 1881	George Campbell
Queanbeyan	James Thompson	Resigned	21 January 1881	Thomas Rutledge
Ninth Legislative Assembly 1877–1880
By-election	Incumbent	Reason	Date	Winner
Windsor	Richard Driver	Death	29 July 1880	Henry McQuade
Illawarra	Samuel Gray	Resigned	7 July 1880	Alexander Stuart
Kiama	Samuel Charles	Prolonged voyage to Europe	2 July 1880	Harman Tarrant
Northumberland	Thomas Hungerford	Resigned (attend to personal business matters)	30 April 1880	Ninian Melville
Clarence	Thomas Bawden	Resigned	7 April 1880	Charles Fawcett
Paddington	John Sutherland	Resigned (company won government contract)	20 February 1880	William Hezlet
East Sydney	Alexander Stuart	Accepted position as Agent-General in London	17 December 1879	Arthur Renwick
University of Sydney	William Windeyer	Accepted an appointment as a Judge of the Supreme Court	26 August 1879	Edmund Barton
East Macquarie	William Suttor, Jr.	Resigned	15 August 1879	Edward Combes
Mudgee 2	Richard Rouse	Result overturned by the Qualifications Committee (no by-election)	(7 March 1879)	David Buchanan
Orange	Edward Combes	Found to have an office of profit under the crown	4 March 1879	Andrew Kerr
Mudgee	John Robertson	Appointed to the Legislative Council	6 January 1879	Richard Rouse
East Maitland	Stephen Scholey	Death	5 June 1878	Henry Badgery
East Macquarie	John Robertson	Elected to two seats,	1 February 1878	Edmund Webb
Eighth Legislative Assembly 1874–1877
By-election	Incumbent	Reason	Date	Winner
Northumberland	Charles Stevens	Financial difficulties	20 July 1877	William Turner
Orange	Harris Nelson	Resigned	(22 February 1877)	Edward Combes
Williams	William Watson	Resigned	February 1877	William Johnston
Mudgee	Stephen Goold	Death	5 October 1876	Richard Rouse
University of Sydney		New seat	8 September 1876	William Windeyer
Carcoar	Solomon Meyer	Resigned due to financial difficulties	(21 June 1876)	Andrew Lynch
Liverpool Plains	Hanley Bennett	Financial difficulties	5 June 1876	Hanley Bennett
Hartley	Thomas Browne	Found to have held a position of profit under the crown	21 April 1876	John Hurley
Parramatta	Hugh Taylor	Resigned as he may have had a position of profit under the crown	20 April 1876	Hugh Taylor
Murrumbidgee	William Forster	Accepted the position of Agent-General in London	(6 March 1876)	Joseph Leary
Upper Hunter	Thomas Hungerford	By-election result voided by Qualifications Committee	5 August 1875	John McElhone
Central Cumberland	Joseph Wearne	Financial difficulties	28 June 1875	William Long
Upper Hunter	Francis White	Death	7 June 1875	Thomas Hungerford
Paterson	William Arnold	Death	18 March 1875	Herbert Brown
Seventh Legislative Assembly 1872–1874
By-election	Incumbent	Reason	Date	Winner
West Maitland	Benjamin Lee	Financial difficulties	4 August 1874	Lewis Levy
East Sydney	James Neale	Resigned	15 July 1874	Charles Moore
East Macquarie	James Martin	Accepted appointment as Chief Justice	1 December 1873	Walter Cooper
Mudgee	Joseph Innes	Appointed to the Legislative Council	8 September 1873	Joseph O'Connor
Hume	James McLaurin	Resigned	31 March 1873	Thomas Robertson
Murray	Patrick Jennings	Resigned	5 August 1872	William Hay
East Sydney	Saul Samuel	Appointed to the Legislative Council	12 June 1872	George Oakes
Parramatta	Hugh Taylor	Disqualified himself at the declaration of the poll as he had a position of profit under the crown	(22 May 1872)	Hugh Taylor
Sixth Legislative Assembly 1869–1872
By-election	Incumbent	Reason	Date	Winner
Mudgee	Henry Stephen	Resigned	2 January 1872	Henry Parkes
New England	Charles Weaver	Resigned	28 August 1871	Samuel Terry
Shoalhaven	Thomas Garrett	Accepted the position of Police Magistrate at Berrima	(28 August 1871)	James Warden
Liverpool Plains	Charles Cowper	Accepted the position of Agent-General in London	9 January 1871	Lewis Levy
Kiama	Henry Parkes	Financial difficulties	(12 January 1871)	John Stewart
Canterbury	Montagu Stephen	Prolonged visit to England	6 January 1871	John Lucas
Goldfields South	Ezekiel Baker	Accepted appointment to the Goldfields Royal Commission	12 December 1870	Ezekiel Baker
Monaro	Daniel Egan	Death	17 November 1870	James Hart
Kiama	Henry Parkes	Financial difficulties	3 November 1870	Henry Parkes
Braidwood	Michael Kelly	Result voided due to electoral irregularities	17 October 1870	Edward Greville
Hastings	Horace Dean	Election overturned as not a British subject (no by-election)	(4 July 1870)	Robert Smith
Wollombi	Joseph Eckford	Financial difficulties	19 September 1870	Joseph Eckford
Hastings	Horace Dean	Found to have held an office of profit under the crown	4 July 1870	Horace Dean
Goldfields South	Ezekiel Baker	Resigned	(11 July 1870)	Ezekiel Baker
Goldfields North	Robert Wisdom	Elected to two seats	18 April 1870	Robert Forster
West Sydney	John Robertson	Financial difficulties	2 March 1870	John Robertson
East Sydney	Henry Parkes	Elected to two seats	23 February 1870	Bowie Wilson
Fifth Legislative Assembly 1864–1869
By-election	Incumbent	Reason	Date	Winner
Braidwood	Joshua Josephson	Accepted an appointment as a Judge of the District Court	(25 September 1869)	Michael Kelly
Goldfields West	George Thornton	Prolonged trip to England	15 February 1869	Walter Church
Central Cumberland	Allan Macpherson	Cause of resignation is unknown	17 December 1868	Samuel Lyons
West Sydney	Samuel Joseph	Prolonged trip to England	15 December 1868	William Campbell
Canterbury	James Pemell	Cause of resignation is unknown	(19 September 1868)	Richard Hill
Goldfields North	George Pickering	Cause of resignation is unknown	6 July 1868	James Hoskins
Upper Hunter	James White	Prolonged trip to England	6 June 1868	Archibald Bell
East Macquarie	David Buchanan	Traveled to England to study for the bar	26 August 1867	John Suttor
Orange	William Forlonge	Financial Difficulty	1 July 1867	George McKay
Central Cumberland	John Hay	Appointed to the Legislative Council	27 June 1867	John Lackey
East Sydney	Charles Cowper	Financial Difficulty	20 March 1867	Marshall Burdekin
Goldfields West	Stephen Donnelly	Cause of resignation is unknown	26 February 1867	George Thornton
Bathurst	James Kemp	Cause of resignation is unknown	(24 December 1866)	William Suttor
East Sydney	John Caldwell	Financial Difficulty	(24 September 1866)	Robert Stewart
Illawarra	Patrick Osborne	Prolonged trip to England	6 September 1866	John Stewart
Clarence	John Laycock	Cause of resignation is unknown	27 August 1866	John Robertson
Tumut	Charles Cowper Jr.	Absent from parliament without leave	20 August 1866	Edward Brown
Williams 2	Frederick Manton	Financial Difficulty	19 April 1866	John Nowlan
Williams 1	Marshall Burdekin	Ministerial by-election	22 January 1866	Frederick Manton
West Sydney	John Robertson	Ministerial by-election	17 January 1866	William Windeyer
Yass Plains	Peter Faucett	Accepted an appointment as a Judge of the Supreme Court	(6 November 1865)	Robert Isaacs
West Sydney 3	John Robertson	Financial Difficulty	(20 October 1865)	John Robertson
West Sydney 2	John Darvall	Retired to England	7 July 1865	Geoffrey Eagar
Gwydir	Tom Dangar	Position of profit under the crown	29 June 1865	Tom Dangar
Monaro	James Martin	Elected to two seats	(10 April 1865)	William Grahame
Canterbury	John Lucas	Elected to two seats	24 February 1865	James Pemell
Fourth Legislative Assembly 1860–1864
By-election	Incumbent	Reason	Date	Winner
East Macquarie	William Suttor	Resigned	6 October 1864	David Buchanan
Kiama	Samuel Gray	Resigned	29 April 1864	Henry Parkes
Braidwood	Merion Moriarty	Death	3 February 1864	Henry Milford
Tumut	Charles Cowper, Jr.	Resigned to oppose Martin in Ministerial by-election	16 November 1863	James Martin
Orange	James Martin	Ministerial – Premier (defeated)	4 November 1863	Charles Cowper, Jr.
Clarence	Clark Irving	Absent for entire session without leave	23 July 1863	Clark Irving
East Maitland	James Dickson	Death	18 June 1863	John Darvall
Central Cumberland	James Atkinson	Resigned (Ill health)	6 June 1863	Allan Macpherson
Goldfields North	James Hoskins	Accepted position as overseer of northern roads	7 April 1863	James Buchanan
Liverpool Plains	Alexander Dick	Resigned	29 January 1863	Marshall Burdekin
West Sydney	William Windeyer	Resigned (Ill health after being shipwrecked)	8 January 1863	Geoffrey Eagar
Northumberland	Thomas Lewis	Financial difficulty	23 December 1862	Atkinson Tighe
Argyle	Terence Murray	Appointed to the Legislative Council	(30 October 1862)	Samuel Emmanuel
Carcoar	William Watt	Resigned	(16 October 1862)	William Dalley
Morpeth	David Buchanan	Financial difficulty	18 September 1862	Edward Close
Orange	John Peisley	Resigned	28 June 1862	James Martin
New England	George Markham	Resigned	2 April 1862	Robert Forster
Wellington	Silvanus Daniel	Resigned	(26 February 1862)	Saul Samuel
Shoalhaven	John Garrett	Resigned	(7 January 1862)	John Robertson
Tenterfield	Robert Meston	Resigned	3 December 1861	Hugh Gordon
Yass Plains	Henry O'Brien	Resigned (Ill health)	(15 August 1861)	Peter Faucett
Camden	John Douglas	Resigned to move to Queensland	(15 August 1861)	David Bell
Hunter	Isidore Blake	Accepted an appointment as a Judge of the District Court	5 August 1861	John Burns
Lower Hunter	Alexander Scott	Appointed to the Legislative Council	19 July 1861	Richard Sadleir
Newtown	Alexander McArthur	Appointed to the Legislative Council	12 July 1861	Thomas Holt
Patrick's Plains	William Lesley	Resigned	(4 July 1861)	Joseph Harpur
Goulburn	Charles Walsh	Resigned as he had achieved his aims of land and Legislative Council reform	13 June 1861	Maurice Alexander
East Sydney	Henry Parkes	Accepted position as immigration promoter in England	29 May 1861	William Forster
Upper Hunter	John Robertson	Appointed to the Legislative Council	15 April 1861	Thomas Dangar
Parramatta	James Byrnes	Resigned (unhappy that he was the second member elected for the seat)	10 April 1861	Arthur Holroyd
Third Legislative Assembly 1859–1860
By-election	Incumbent	Reason	Date	Winner
Tumut	Daniel Deniehy	Elected to two seats and previous by-election voided due to voting irregularities	(1 November 1860)	Charles Cowper, Jr.
Braidwood	Frederick Cooper	Resigned	10 August 1860	Merion Moriarty
Morpeth	Edward Close	Resigned	7 August 1860	Samuel Cohen
Wellington	Nicolas Hyeronimus	Death	26 July 1860	Silvanus Daniel
Wollombi	William Cape	Resigned	17 May 1860	Joseph Eckford
Tumut	George Lang	Resigned (political ennui)	10 May 1860	Daniel Deniehy
East Macquarie	Thomas Hawkins	Resigned	10 May 1860	Daniel Deniehy
St Leonards	Edward Sayers	Resigned	2 May 1860	James Farnell
Hunter	Richard Jones	Resigned	(23 April 1860)	Isidore Blake
Liverpool Plains	Andrew Loder	Resigned after the defeat of the Foster Government	10 April 1860	Charles Kemp
Windsor	William Dalley	Prolonged visit to Europe resulting by-election	12 March 1860	William Walker
Williams	Stephen Dark	Resigned	16 February 1860	Alexander Campbell
Canterbury	Edward Flood	Resigned	4 February 1860	John Lucas
East Sydney	Charles Cowper	Was nominated and elected without his consent at previous by-election	20 January 1860	Peter Faucett
West Macquarie	John McPhillamy	Resigned	(21 December 1859)	Henry Mort
Mudgee	Lyttleton Bayley	Resigned after losing ministerial post	19 December 1859	Samuel Terry
East Sydney	Charles Cowper	Resigned (Ill health)	10 November 1859	Charles Cowper
Illawarra	John Hargrave	Appointed to Legislative Council	28 October 1859	Samuel Gordon
East Macquarie	William Suttor	Resigned	6 October 1859	Thomas Hawkins
Yass Plains	Thomas Laidlaw	Found to have a position of profit under the crown	(15 September 1859)	Thomas Laidlaw
East Maitland	Joseph Chambers	Appointed Crown Prosecutor	15 September 1859	James Dickson
Second Legislative Assembly 1858–1859
By-election	Incumbent	Reason	Date	Winner
East Camden	Robert Owen	Accepted an appointment as a Judge of the District Court	21 March 1859	John Hargrave
New England and Macleay	Abram Moriarty	Resigned	(26 November 1858)	James Hart
Cumberland (North Riding)	Henry Parkes	Financial difficulties	(13 September 1858)	John Plunkett
First Legislative Assembly 1856–1858
By-election	Incumbent	Reason	Date	Winner
Moreton, Wide Bay, Burnett and Maranoa	Gordon Sandeman	Resigned	(19 November 1857)	Patrick Leslie
Cumberland (North Riding)	John Darvall	Resigned	11 December 1857	Thomas Smith
Northumberland Boroughs	George Nichols	Death	(3 November 1857)	James Dickson
Cumberland (South Riding)	William Manning	Resigned	12 June 1857	James Byrnes
Argyle	John Plunkett	Appointed to the Legislative Council	(13 February 1857)	Daniel Deniehy
Sydney City	Henry Parkes	Financial difficulties	29 December 1856	William Dalley
Cumberland (South Riding)	Ryan Brenan	Result voided by the Elections and Qualifications Committee	(4 November 1856)	Stuart Donaldson
Sydney Hamlets	Stuart Donaldson	Ministerial (defeated)	10 October 1856	John Campbell
Cumberland (South Riding)	Elias Weekes	Elected for two seats	21 August 1856	Ryan Brenan
Northumberland Boroughs	Bourn Russell	Result overturned by Qualifications Committee (no by-election)	(5 August 1856)	Elias Weekes
Bathurst County	John Plunkett	Elected for two seats	19 June 1856	William Suttor
Western Division of Camden	James Macarthur	Believed poll to be unconstitutional	(16 June 1856)	James Macarthur

Causes

A by-election may occur whenever there is a vacancy in the Legislative Assembly. Vacancies can occur for reasons including:

• Death
• Voluntary resignation for any reason; historically these reasons have included:
  • Retirement
  • Health issues
  • Family or business commitments
  • Prolonged absence from the state—this occurred most commonly in the period when travel to Europe required a long sea voyage
  • Loss of cabinet position, e.g., the resignation of Reba Meagher in 2008 after she lost the position of Minister for Health
  • Matters of principle, e.g., Billy Dunn resigned from the seat of Mudgee in 1911 after disagreeing with his party's land ownership legislation.
  • Resignation or expulsion from a political party
  • To create a vacancy for a party leader who did not have a seat. This occurred most recently in 1986 when Rockdale MLA Brian Bannon resigned to enable newly elected party leader Barrie Unsworth to transfer from the Legislative Council to the Legislative Assembly.
  • Public disgrace
  • As a result of an inducement from an opposing party and thus create the potential for that party to increase its representation e.g. Independent MLA Alick Kay accepted an appointment to the Metropolitan Meat Board in 1927. Under a controversial use of the Legislative Assembly (Casual Vacancies) Act, he was replaced by Labor's Arthur Tonge; this gave the government of Jack Lang a secure majority in the house.
• Constitutional ineligibility to be a Member of the Legislative Assembly, including:
  • Election result voided or overturned on appeal—appeals were initially made to the Qualifications Committee of the Assembly but since 1928 they have been determined by the Court of Disputed Returns
  • Election to two seats—in which case the member was required to resign from one seat
  • Appointment or election to the Legislative Council This occurred most commonly prior to 1936, when members of the council were appointed for life by the governor
  • Election to another parliament, particularly federal parliament—members are required to resign prior to the issuing of the writs for the other parliament's election
  • Having or accepting a position of profit under the crown
  • Not being a citizen of Australia
  • Non-residence in New South Wales for more than 6 months prior to election
  • Becomes of "unsound mind"
  • Insolvency
  • Conviction for a major criminal offence or, since 2007, having faced trial on a charge of sexual abuse of a minor
  • Absence from the house for an entire session without leave
  • Expulsion from the house for infamous conduct
  • Ministerial appointment Until 1904, members appointed to a ministerial position were required to face a by-election. These were generally uncontested. The political instability of New South Wales in the Nineteenth century caused a very large number of these by-elections and for convenience they have not been listed unless the minister was defeated.

It is now a convention that a by-election is not held if a vacancy occurs within 3–4 months of an expected dissolution of the parliament.