The Montana State Legislature is made up of two chambers, the Senate and the House of Representatives. The Constitution of Montana limits the size of the Senate to no fewer than 40 and no more than 50 members and the size of the House of Representatives to no fewer than 80 and no more than 100 members. Each house is responsible for choosing its officers, creating committees and establishing its own rules. The Montana Legislature meets for 90 days every odd numbered year, beginning the first Monday in January, or the following Wednesday if the first Monday is New Years Day. The first State Legislature convened on November 23, 1889, fifteen days after Montana became a state. Each following Legislature has been numbered sequentially.

The 58th Montana Legislature met from January 3rd to April 26th, 2005. There were 15 standing committees in the Senate and 16 standing committees in the House. The leaders of the Senate were Bob Keenan (R-President), Walter McNutt (R-President Pro Tempore), Fred Thomas (R-Majority Leader), Corey Stapleton (R-Majority Whip), Jon Tester (D-Minority Leader) and Jon Ellingson (D-Minority Whip). The leaders of the House were Coug Mood (R-Speaker), Jeff Laszloffy (R-Speaker Pro Tempore), Roy Brown (R-Majority Leader), Cindy Younkin and John Brueggeman (R-Majority Whips), David Wanzenried (D-Minority Leader), Tim Dowell and Monica Linden (D-Minority Whips).

Sources: The Constitution of the State of Montana as adopted by the Constitutional Convention March 22, 1972, and as ratified by the people, June 6, 1972, referendum no. 68, http://leg.mt.gov/bills/mca_toc/Constitution.htm; "Organization of the Montana Legislature," The Montana Legislature, http://www.leg.mt.gov/css/About-the-Legislature/organization.asp; "2003 Legislative Session," The Montana Legislature, http://leg.mt.gov/css/Sessions/58th/default.asp