New Mexico Prenuptial Agreement
New Mexico prenups are governed by the NM Uniform Premarital Agreement Act (NMSA §§ 40-3A-1 to -10), effective July 1, 1995. NMSA § 40-3A-4(B) bars any agreement from "adversely affecting" spousal support, making alimony waivers void per se (Rivera v. Rivera, 2010-NMCA-106). NM also voids clauses affecting custody, abode, or career, and requires notarization under § 40-3A-3.
Bottom line: New Mexico earns an F grade. Prenups can keep property separate and override the community-property 50/50 default, but cannot limit alimony at all. A prenup is still far better than none to reduce divorce asset splits.
New Mexico Prenup Enforceability Rating: F
New Mexico Prenup Laws: Key Statutes Explained
Uniform Premarital Agreement Act, NMSA 1978, §§ 40-3A-1 to -10 ("NM UPAA")
New Mexico has passed the UPAA but doesn't allow and modification to alimony/spousal support from the state statute. Prenups can keep property separate and avoid costly divorce settlements, however, they cannot affect state guidelines for alimony upon divorce.
Separate Property
All assets can remain separate property, avoiding costly divorce settlements. NM is a community-property state, so without a prenup, assets acquired during marriage are split 50/50 regardless of title. A prenup overrides that default and keeps designated assets, income, and business interests separate.
Unconscionability Standard — NMSA § 40-3A-7 Two-Prong Test
A prenup is unenforceable if the challenging party proves: (1) involuntary execution due to coercion or undue pressure; OR (2) the agreement was unconscionable at execution AND (a) lacked fair and reasonable disclosure of the other's property/obligations, (b) no written waiver of disclosure, AND (c) challenging party lacked adequate knowledge of the other's finances.
Spousal Support Cannot Be Modified
Unlike most states, New Mexico flatly prohibits any prenup provision that adversely affects spousal support under NMSA § 40-3A-4(B). Waivers, caps, formulas, and limitations are all per se void — and without a severability clause, an invalid support clause can void the entire prenup (Rivera v. Rivera, 2010-NMCA-106). At divorce, spousal support is determined exclusively by the statutory factors in NMSA § 40-4-7, regardless of what the prenup says. Best practice: stay completely silent on support.
Timing
No minimum specified, but we recommend signing the prenup 60+ days before the wedding, with both parties having 2-3 weeks to review the final version to minimize challenge risk. Reach out to an attorney at least 4-6 months before the wedding with your draft prenup. Better yet, sign the prenup before proposing.
Independent Counsel
Not required, but separate counsel dramatically strengthens enforceability if the agreement is later challenged. Lebeck v. Lebeck upheld a husband-drafted prenup largely because the wife had independent counsel. NM courts closely scrutinize whether parties had opportunity for independent legal review.
Financial Disclosure
"Fair and reasonable disclosure" of property and financial obligations required under NMSA § 40-3A-7, or written waiver. PerfectPrenup includes both.
Notarial Acknowledgment Required
Beyond writing and both signatures, NMSA § 40-3A-3 requires the prenup to be acknowledged (notarized). This is a NM-specific addition that most UPAA states omit. Informal prenups — even with proof of mutual assent — are unenforceable.
Moderate Burden to Challenge
Challenging party must prove either involuntary execution or unconscionability plus lack of disclosure by preponderance of evidence. NM courts favor enforcement of validly executed prenups but strictly enforce § 40-3A-4(B)'s public-policy limits. Prenuptial agreements in Next Mexico cannot affect alimony and must include a robust severability clause.
Child Support and Custody
Child support, custody, and visitation clauses are unenforceable under § 40-3A-4(B) and could undermine the entire agreement. Do not include.
New Mexico Prenuptial Agreement Court Cases
Rivera v. Rivera, 2010-NMCA-106, 149 N.M. 66, 243 P.3d 1148
The Court of Appeals struck down the entire premarital agreement because its spousal-support waiver was per se unconscionable under NMSA § 40-3A-4(B), and, without a severability clause, the invalid waiver sank the whole contract.
Matter of Estate of McKim, 1991-NMSC-020, 111 N.M. 517, 807 P.2d 215
The Supreme Court held that an antenuptial "separate property" agreement did not control the characterization of the Ridgecrest and Yale properties because the spouses' later conduct — transfers, refinancings, and lender-required reconveyances — showed a contrary intent, and a constructive trust was imposed for Mrs. McKim's business.
Gabriele v. Gabriele, 2018-NMCA-042, 421 P.3d 828
The Court of Appeals applied the Beals/Trujillo constructive-fraud presumption to void four post-marital separate-property agreements that had stripped the husband of roughly $128,000 in community interest for zero consideration, because the advantaged spouse failed to prove adequate consideration, full disclosure, and independent advice.
Russ v. Russ, 2021-NMSC-014
The Supreme Court held that the Supremacy Clause requires full retroactive application of Howell v. Howell, 137 S. Ct. 1400 (2017), so a 2006 marital settlement agreement awarding the wife 50% of the husband's military retirement could not be enforced as a $22,000+ reimbursement once he waived retirement pay for Combat-Related Special Compensation.
Autrey v. Autrey, No. A-1-CA-38534 (N.M. Ct. App. Apr. 5, 2022)
Without a prenup, the Court of Appeals affirmed that the AJAC construction business started during the marriage was community property, reversed only the district court's finding that the Corona home was in a revocable (rather than irrevocable QPRT) trust, and confirmed that revocable trusts don't shield marital assets from division.
Lebeck v. Lebeck, 1994-NMCA-102, 118 N.M. 367, 881 P.2d 727
The Court of Appeals upheld a husband-drafted prenup against challenges of duress and unfairness, holding that the challenger bears the burden of proof, that a short pre-wedding signing window and a "no prenup, no marriage" ultimatum are not duress, and that the wife's access to independent counsel was dispositive — leaving her with no alimony and no community property.
Herrera v. Herrera, 1999-NMCA-034, 126 N.M. 705, 974 P.2d 675
The Court of Appeals enforced an unsigned marital settlement agreement based on testimony of mutual assent — a holding that should be treated as cautionary for prenup drafters because NMSA § 40-3A-3 imposes a stricter writing/signing/acknowledgment requirement that Herrera's flexible contract rule does not override.
5-Step Checklist: How to Sign & Execute a Prenup in New Mexico
Step 1: Download and read the New Mexico prenuptial agreement
Start with our free template. It is written for New Mexico-specific statutes and case law under the Uniform Premarital Agreement Act, NMSA §§ 40-3A-1 to -10. Read it in full — know what you are getting into legally with marriage. The 15+ pages is written thoroughly to include rebuttals to common legal challenges and fallback provisions.
Step 2: Draft changes on your own
See a clause you don't like? Copy it into an AI like Claude, explain what you'd like to change or what you want the clause "to do." Save any changes as a separate alternate version — don't overwrite the original. Bring both versions to your attorney review. Note: AI is often gender-biased and crafts terms beyond what is legally required. Push back on its output. Also: do NOT add spousal support or alimony clauses — NM flatly prohibits them under § 40-3A-4(B), and an invalid support clause can void the entire agreement.
Step 3: Find a matrimonial or divorce lawyer in New Mexico
Find a matrimonial or divorce attorney in your state. Avvo, Findlaw, and Justia are good. Look for someone with 10+ years experience. Call or email and ask them how much to review your draft prenup and help with signing. Send them your draft.
Step 4: Meet your lawyer 4–6 months before the wedding
Our recommendation: sign the prenup before proposing. That way, you both get the legal work out of the way, and you know this is the right person to marry. Already proposed? 4–6 months before the wedding should leave you enough time to give your spouse 1–2 weeks to review the final draft and have it signed 60+ days before the wedding. Last-minute pressure and short review windows are leading challenge grounds under NM's voluntariness and unconscionability tests in § 40-3A-7 — Rivera v. Rivera voided a prenup signed days before the wedding.
Step 5: Sign with your attorney and store the agreement
New Mexico requires the prenup to be in writing, signed by both parties, AND acknowledged before a notary under NMSA § 40-3A-3 — acknowledgment is a NM-specific requirement most UPAA states omit. Most attorneys are also notaries, so your attorney can notarize on the spot, satisfying all requirements in one signing ceremony. If you don't have an attorney (highly against our recommendation), you must have a separate notary present. An unsigned or unacknowledged agreement is invalid regardless of everything else. Each party keeps a signed original, and so should each party's attorney. Store yours somewhere secure like a safety deposit box. Create a .pdf and save it via a backup drive and email.
New Mexico Prenuptial Agreement: Frequently Asked Questions (2026)
1. Are prenuptial agreements enforceable in New Mexico?
Yes. New Mexico adopted the Uniform Premarital Agreement Act (NMSA §§ 40-3A-1 to -10) effective July 1, 1995. Prenups signed after that date are enforceable if they're in writing, signed by both parties, acknowledged (notarized), voluntarily executed, and not unconscionable when signed. However, New Mexico does not allow alimony or spousal support to be modified - largely gutting the utility of prenups to begin with.
2. How much does a prenup cost in New Mexico?
Costs vary by complexity. Straightforward prenups with flat-fee arrangements typically run in the low thousands per side. Complex prenups involving business valuations, multiple properties, out-of-state assets, or significant separate property can run higher. Because each party needs independent counsel, budget for two separate attorney fees. Ask for a written estimate that includes drafting, disclosure review, negotiation, and the signing ceremony. WIth PerfectPrenup.io, you only needan attorney to review and sign, which should reduce the cost to $500-$1,000 per side.
3. How long before the wedding should I sign a prenup in New Mexico?
No statutory minimum, but we recommend signing 60+ days before the wedding, with both parties having 2-3 weeks to review the final draft. Start engaging attorneys 4-6 months before the wedding. Last-minute pressure is one of the most successful grounds for invalidating a prenup under § 40-3A-7's voluntariness test — Rivera v. Rivera voided an agreement signed days before the wedding. Better yet: sign before proposing.
4. Can you waive spousal support (alimony) in a New Mexico prenup?
No. New Mexico is one of only three states (along with Iowa and South Dakota) that flatly prohibits waiving spousal support in a prenup. Under NMSA § 40-3A-4(B), any clause that "adversely affects" spousal support is void and was held per se unconscionable in Rivera v. Rivera, 2010-NMCA-106. At divorce, alimony will be determined by the statutory factors in NMSA § 40-4-7 regardless of what your prenup says.
5. Do I need a lawyer for a prenup in New Mexico?
Not legally required, but strongly recommended. New Mexico courts closely scrutinize whether both parties had opportunity for independent legal review. Lebeck v. Lebeck upheld a husband-drafted prenup largely because the wife had independent counsel. Each party should have their own lawyer — shared counsel creates conflict-of-interest problems that can undermine enforceability if challenged.
6. Does a prenup need to be notarized in New Mexico?
Yes. NMSA § 40-3A-3 requires prenups to be in writing, signed by both parties, AND acknowledged (notarized). Acknowledgment is a New Mexico-specific requirement most UPAA states omit. An unsigned or unacknowledged prenup is invalid regardless of everything else. Most attorneys are also notaries, so your attorney can notarize on the spot.
7. What cannot be included in a New Mexico prenup?
NMSA § 40-3A-4(B) voids any clause that adversely affects: (1) spousal support, (2) a child's right to support, (3) child custody or visitation, (4) either party's choice of abode, or (5) either party's freedom to pursue career opportunities. Relocation restrictions, career-sacrifice liquidated damages, and alimony waivers that would survive in most other states cannot survive in New Mexico.
8. How is property divided in New Mexico without a prenup?
New Mexico is one of nine community-property states. Under NMSA § 40-3-8, assets and debts acquired during marriage are presumed community property and divided 50/50 at divorce, regardless of whose name is on the title. Property owned before marriage, or received during marriage by gift or inheritance, remains separate — but commingling can convert separate property into community property. A prenup overrides this default.
9. Can a New Mexico prenup be invalidated or thrown out?
Yes. Under NMSA § 40-3A-7, a prenup is unenforceable if the challenging party proves either (1) involuntary execution, OR (2) the agreement was unconscionable at signing AND lacked fair financial disclosure, no written waiver of disclosure, and the challenger had no adequate knowledge of the other's finances. Support-waiver clauses without a severability clause can void the entire agreement under Rivera.
10. Does a New Mexico prenup cover child support and custody?
No. Child support, custody, and visitation cannot be determined by a prenup under § 40-3A-4(B). Child support is the child's right, not the parents', and custody must reflect the child's best interests at the time of divorce — not a pre-arranged formula. Including these clauses could undermine the entire agreement. Do not include.
11. Can we amend or revoke a New Mexico prenup after marriage?
Yes. Under NMSA § 40-3A-6, you can amend or revoke a prenup after marriage by a written agreement signed and acknowledged by both parties — OR by a "consistent and mutual course of conduct" that shows amendment or revocation. This conduct loophole is unusual among UPAA states. In Estate of McKim, antenuptial separate-property designations were undone by the couple's later transactions. Post-marriage behavior can quietly unwind the deal.
12. Can we choose another state's law to govern our New Mexico prenup?
Yes, NMSA § 40-3A-4(A)(6) allows parties to choose the governing law. Couples with out-of-state ties sometimes select a sister-state's UPAA (e.g., California, Texas, Colorado) to avoid NM's § 40-3A-4(B) restrictions. But a NM court will still apply NM public policy as a floor to bar spousal-support waivers if the couple actually lives in NM. Choice-of-law clauses are strongest when the chosen state has genuine connections to the marriage.