Common law marriage—also known as marriage without formalities or informal marriage—is marriage without a wedding or marriage ceremony and without a marriage license. Some states recognize common law marriage under certain circumstances—such as when the parties agree to be married, live together (cohabit) after agreeing to be married, and represent to others that they are married (holding themselves out as a married couple).

Other states previously recognized common law marriages, but no longer recognize such marriages after a certain date on which the law was changed—usually by statute. In other states, common law marriage has not been recognized by the legislature in a statute, but the courts have recognized common law marriage in court opinions or case law.

In New Mexico, common law marriages are not recognized. This means that couples who cohabit and hold themselves out as married without formalizing their relationship through a marriage license and ceremony do not acquire the legal status of marriage in the eyes of New Mexico law. However, New Mexico does recognize common law marriages that were established in other states where such marriages are legally recognized. This is in accordance with the principle of 'full faith and credit' which generally requires states to recognize the 'public acts, records, and judicial proceedings' of other states. Therefore, if a couple has a valid common law marriage from another state, New Mexico would acknowledge their marital status. It is important for individuals in such relationships to understand their legal rights and obligations, and they may wish to consult with an attorney for personalized legal advice.