The 18th Arizona State Legislature, consisting of the Arizona State Senate and the Arizona House of Representatives, was constituted in Phoenix from January 1, 1947 to December 31, 1948, during the fourth of Sidney Preston Osborn's four consecutive terms as Governor of Arizona. The number of senators and house members remained constant at 19 and 58, respectively. The Democrats controlled one hundred percent of the senate. while the Republicans gained four house seats, to a total of five.
The Legislature met for the regular session at the State Capitol in Phoenix on January 13, 1947; and adjourned on March 20.[1] There were seven special sessions, the first of which was held from June 9 through June 23, 1947,[2]: 376 the second was held from June 18 – July 1, 1947,[2]: 402 the third was held between January 5 – 21, 1948,[2]: 515 the fourth from January 22- February 17, 1948,[2]: 538 the fifth spanned February 18 – March 12, 1948,[2]: 553 The sixth was from March 12–25, 1948,[2]: 635 and the seventh from September 13 – October 14, 1948.[2]: 661