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.
