Missouri would hold presidential primary elections in March instead of February under a bill on its way to Gov. Jay Nixon.
House members approved the legislation Monday on a vote of 101-47. The Senate passed it 25-7 in April.
The legislation comes after Missouri had a confusing 2012 presidential election process. State law called for a February primary, but the national political parties sought to discourage most states from voting that early.
Missouri Republicans decided to disregard the primary results and use later caucuses to determine which candidate delegates would support at the Republican National Convention.
Under this year's bill, Missouri's next presidential primary would take place March 15, 2016.