Bigamy is the act of marrying one person while being legally married to another. Polygamy is the practice or custom (often religious) of having more than one wife or husband at a time. Most states prohibit a party from having more than one marriage license at a time, and in most states bigamy is a crime.
In Missouri, both bigamy and polygamy are prohibited by law. Under Missouri statutes, bigamy is considered a crime. Specifically, Missouri law states that a person commits the offense of bigamy if, while married, he or she purports to marry another person or cohabits with another person in this state under the appearance of being married. Bigamy is classified as a Class E felony, which carries potential penalties including fines and imprisonment. There are no provisions in Missouri law that allow for polygamous marriages, regardless of religious or cultural practices. As such, any marriage license obtained while already legally married to another individual would be invalid, and the act of entering into such a marriage would be subject to legal penalties.