Mo. Rev. Stat. § 115.565
Not later than thirty days after the official announcement of the election result is issued by the secretary of state, any candidate who wishes to contest the election for an office provided in section 115.563 shall file a verified petition with the president of the senate or the speaker of the house, as the case may be. In the case of contests based on the qualifications of a candidate for an office provided in section 115.563, not later than thirty days after the results of the general election have been certified by the secretary of state, any candidate who wishes to contest the qualifications of another candidate shall file a verified petition with the president of the senate or the speaker of the house, as the case may be. The petition shall set forth the points on which the contestant wishes to contest the election and the facts he will prove in support of such points. The state senate or the state house of representatives, as the case may be, shall have exclusive jurisdiction over all matters relating to the contest and may issue appropriate orders, under the hand of the president of the senate or the speaker of the house, to all election authorities in the area in which the contested election was held.
§ 115.565, RSMo
Effective 5/20/1982