Mo. Rev. Stat. § 474.120
Current with changes from the 2023 Legislative Session
The rights of inheritance or any other statutory rights of a surviving spouse of a decedent who dies intestate shall be deemed to have been waived if prior to, or after, the marriage such intended spouse or spouse by a written contract did agree to waive such rights, after full disclosure of the nature and extent thereof, including the nature and extent of all property interests of the parties, and if the thing or promise given to the waiving party is a fair consideration under all the circumstances.
§ 474.120, RSMo
RSMo 1939 § 334, A.L. 1955 p. 385 § 247, A.L. 1963 p. 655