The commission said in a news release Wednesday the agreement will take effect on April 1. The commission staff estimated a typical residential customer's monthly bill will increase by about $3.70.
Ameren Missouri filed a rate request in July 2016 seeking a revenue increase of about $206.4 million.
The utility has said it needed the increased revenue because of new capital investments, transmission and distribution projects, as well as higher transmission operator charges and reduced revenue demand on its system.
The agreement continues a clause that allows Ameren Missouri to adjust customer bills up to three times a year.
Ameren Missouri serves about 1.26 million customers in Missouri.