New Mexico Prenuptial Agreement Laws: Rules and Enforceability (2026)

New Mexico enforces prenuptial agreements under its Uniform Premarital Agreement Act, NMSA 40-3A-1 to 40-3A-10. The agreement must be in writing, signed by both parties and acknowledged (NMSA 40-3A-3), and it may not adversely affect the right of a child or a spouse to support (NMSA 40-3A-4(B)).

Information last verified on 2026-10-08. This article has not been reviewed by a licensed lawyer.

Jurisdiction scope: This article covers premarital agreements under New Mexico's Uniform Premarital Agreement Act (NMSA 40-3A-1 to 40-3A-10), the community property presumption in NMSA 40-3-12(A), and the Court of Appeals decision in Rivera v. Rivera, 2010-NMCA-106. It covers the Chapter 40, Article 2 rules on contracts between spouses only briefly and does not cover postnuptial agreement case law, cohabitation agreements, or other states' law. It is information only, not a template or drafting guide. For divorce, see New Mexico divorce laws.

Which law governs prenups in New Mexico

New Mexico adopted the Uniform Premarital Agreement Act in Laws 1995, chapter 61, codified at NMSA 40-3A-1 to 40-3A-10. Section 40-3A-1 provides: "This act may be cited as the 'Uniform Premarital Agreement Act'."

The Act as compiled in NMSA 40-3A-1 to 40-3A-10 has no section stating which agreements it applies to by date, so this page does not say how it treats agreements signed before the Act took effect.

Formal requirements

NMSA 40-3A-3 provides:

"A premarital agreement must be in writing, signed by both parties and acknowledged. It is enforceable without consideration."

So the statute requires three things: a writing, both signatures, and acknowledgment. Acknowledgment is part of the statutory text, not an optional extra. No consideration is needed, and under NMSA 40-3A-5 the agreement becomes effective on marriage.

What a New Mexico prenup cannot do

New Mexico's version of the Act protects support rights for a spouse as well as a child. NMSA 40-3A-4(B) provides:

"A premarital agreement may not adversely affect the right of a child or spouse to support, a party's right to child custody or visitation, a party's choice of abode or a party's freedom to pursue career opportunities."

That list covers four areas: support for a child or spouse, custody and visitation, where a party lives, and career opportunities.

Spousal support waivers and Rivera v. Rivera

A leading decision is Rivera v. Rivera, 2010-NMCA-106, 149 N.M. 66, 243 P.3d 1148, decided by the New Mexico Court of Appeals in 2010. The New Mexico Supreme Court denied certiorari on October 13, 2010.

The court held that a premarital agreement waiving each spouse's right to support violated the public policy in 40-3A-4(B). In its words, "the agreement is contrary to the public policy expressed in Section 40-3A-4(B) and is therefore unconscionable." In that case the disclosure and knowledge conditions were undisputed. Because the agreement had no severability clause, the wife made no argument for keeping the rest of it, and the court could not tell whether the support waiver had been traded for other terms, the court held the entire agreement unconscionable and reversed.

For how spousal support works without an agreement, see New Mexico alimony laws.

When a New Mexico prenup is not enforceable

NMSA 40-3A-7 sets the test:

"A premarital agreement is not enforceable if the party against whom enforcement is sought proves that: (1) that party did not execute the agreement voluntarily; or (2) the agreement was unconscionable when it was executed and, before execution of the agreement, that party:"

The conditions in paragraph (2) are that the party was not provided a fair and reasonable disclosure of the other party's property or financial obligations, did not voluntarily and expressly waive further disclosure in writing, and did not have, and could not reasonably have had, adequate knowledge of them. All three must be shown along with unconscionability. Under the same section, the court decides unconscionability as a matter of law.

Three points about the Act's text:

• Burden. The party resisting enforcement must prove the ground. The Act does not state a standard of proof.
• Lawyers. The Act's text does not require independent counsel. Lawyers licensed in New Mexico can draft or review these agreements.
• Timing. The Act's text does not set a waiting period between signing and the wedding.

Changing or revoking a prenup after the wedding

NMSA 40-3A-6 provides that, after marriage, a premarital agreement "may be amended or revoked only by a written agreement signed and acknowledged by the parties or by a consistent and mutual course of conduct." The amendment or revocation needs no consideration.

The course-of-conduct option means the parties' behavior during the marriage can matter, not only later paperwork.

Time limits and void marriages

Limitations tolled. Under NMSA 40-3A-9, the statute of limitations that applies to the agreement "is tolled during the marriage of the parties to the agreement. However, equitable defenses limiting the time for enforcement, including laches and estoppel, are available to either party."

Void marriage. If the marriage turns out to be void, NMSA 40-3A-8 makes the agreement "enforceable only to the extent necessary to avoid an inequitable result."

Postnuptial agreements

New Mexico has no statute titled postnuptial agreement, but Chapter 40, Article 2 governs contracts between spouses. Spouses may contract with each other about property, subject to the common-law rules for people in a confidential relationship (NMSA 40-2-2). They cannot otherwise alter their legal relations by contract, except to agree in writing to an immediate separation and provide for support during it (40-2-8). Contracts for marriage settlements must be in writing and executed and acknowledged or proved like a grant of land (40-2-4). Section 40-3A-6, above, covers amending a premarital agreement after the wedding. A lawyer licensed in New Mexico can advise on an agreement made during the marriage.

Property division without a prenup

New Mexico is a community property state. NMSA 40-3-12(A) provides: "Property acquired during marriage by either husband or wife, or both, is presumed to be community property." For how property is divided in a divorce, see New Mexico divorce laws.

Disclaimer: This article provides general legal information about premarital agreements under New Mexico's Uniform Premarital Agreement Act (NMSA 40-3A-1 to 40-3A-10). It is not legal advice and is not a template. The information was verified on 2026-10-08, and the law can change. For advice about your situation, consult a lawyer licensed in New Mexico.

Related

• Prenuptial agreement laws in every state
• New Mexico divorce laws
• New Mexico alimony laws
• New Mexico child custody laws

Last updated: 2026-10-08.

Frequently Asked Questions

Are prenups enforceable in New Mexico?

Yes. Under NMSA 40-3A-7, a premarital agreement is enforceable unless the party resisting it proves involuntary execution, or unconscionability when signed together with the disclosure and knowledge conditions in that section.

Does a prenup need to be acknowledged in New Mexico?

Yes. NMSA 40-3A-3 requires a premarital agreement to be in writing, signed by both parties and acknowledged.

Can a New Mexico prenup waive alimony?

NMSA 40-3A-4(B) bars an agreement from adversely affecting a spouse's right to support. In Rivera v. Rivera, 2010-NMCA-106, the Court of Appeals held a mutual support waiver unconscionable and, because the agreement had no severability clause and no one argued for keeping the rest, held the whole agreement unconscionable.

Can a prenup decide custody in New Mexico?

No. Under NMSA 40-3A-4(B), a premarital agreement may not adversely affect a party's right to child custody or visitation, or a child's right to support.

Do both spouses need a lawyer for a New Mexico prenup?

The Act's text does not require independent counsel. Its enforcement test in NMSA 40-3A-7 turns on voluntariness, unconscionability, disclosure and knowledge.

Can a New Mexico prenup be changed after the wedding?

Yes. Under NMSA 40-3A-6, by a written agreement signed and acknowledged by both parties, or by a consistent and mutual course of conduct.