A marriage affidavit is a written declaration made under oath before an authorized official. Its purpose is to recognize a marriage as a legal bond. It serves as state-recognized proof of the relationship.

Marriage affidavits tend to vary from state to state, but most have similar requirements regarding information that must be present on the official document. The document typically includes the name of both partners and the date they were married, with the signature and address of the witness to the ceremony.

For the marriage affidavit to be valid, the couple must share the same regular permanent residence and living expenses, have a close relationship and not be married to anyone else. The couple must also be of valid marrying age, not be related by blood and be mentally competent to sign the document.