New Mexico: Prenuptial Agreement Requirements

Requirements one by one

New Mexico uses a modified Uniform Act

NMSA 1978 §§ 40-3A-1-40-3A-3 identify the Uniform Premarital Agreement Act,
define the agreement, and impose its basic form. New Mexico keeps the familiar
uniform-act enforcement structure but makes important state-specific changes to
acknowledgment, support and personal rights, and later amendment.

The Act governs ordinary agreements made by prospective spouses in
contemplation of marriage and intended to take effect upon marriage.

The agreement needs writing, signatures, and acknowledgment

Section 40-3A-3 requires a writing signed by both parties and acknowledged. The
agreement is enforceable without consideration, so no separate payment or
property transfer is required.

The Act states no additional witness, attestation, oath, or recording condition.
An unacknowledged form does not satisfy New Mexico's express statutory
formality.

Marriage activates the agreement

Section 40-3A-2 defines the agreement as one intended to be effective upon
marriage, and § 40-3A-5 states the same activation rule directly. A form should
not treat the signing date as the legal effective date before the marriage
occurs.

Disclosure has waiver and knowledge alternatives

Section 40-3A-7(A)(2) requires execution-time unconscionability plus all three
disclosure failures: no fair and reasonable disclosure, no voluntary express
written waiver of further disclosure, and no actual or reasonably available
adequate knowledge.

Those elements are conjunctive. Lack of a financial schedule alone does not
complete the defense if a qualifying written waiver or adequate knowledge
defeats another required element.

Counsel and timing have no fixed statutory minimum

The Act does not require independent counsel, prescribe a counsel advisement or
waiver form, create a final-draft review period, or require signing a set number
of days before the wedding.

Voluntariness remains an independent requirement under § 40-3A-7(A)(1). A court
can therefore examine pressure and the execution circumstances even though New
Mexico has no numerical wedding countdown.

The statutory fairness test has two routes

NMSA 1978 § 40-3A-7 makes involuntary execution sufficient by itself to defeat
enforcement. The alternative route requires execution-time unconscionability
and all three disclosure failures.

New Mexico expressly assigns both voluntariness and unconscionability to the
court as matters of law. The section does not state a general enforcement-time
unconscionability or changed-circumstances review for every permissible term.

Spousal support may not be adversely affected

New Mexico departs sharply from the baseline UPAA. Section 40-3A-4(B) bars a
prenup from adversely affecting either spouse's right to support; it does not
merely add a public-assistance floor to an otherwise permitted waiver.

Rivera v. Rivera applied that rule to provisions waiving support, maintenance,
and medical expenses. The Court of Appeals held the provisions contrary to the
statute's public policy and, because severability had not been established,
treated the entire agreement as unconscionable.

Child and personal rights receive express protection

Across NMSA 1978 §§ 40-3A-4-40-3A-6, New Mexico sets subject limits, the
marriage-time effect, and the later-change rule. The § 40-3A-4(B) sentence
protects a child's support, a party's custody or
visitation rights, each party's choice of abode, and each party's freedom to
pursue career opportunities. Other contracted matters also may not violate
public policy.

Custody remains subject to later court review. NMSA 1978 § 40-4-9.1(D) permits
the court to follow a parental custody agreement unless it determines that the
agreement is not in the child's best interests.

Conduct can amend or revoke the agreement

NMSA 1978 § 40-3A-6 supplies two routes after marriage. The parties may use a
written agreement that both sign and acknowledge, or their consistent and
mutual course of conduct may evidence amendment or revocation.

Either route is enforceable without consideration. A form stating that only a
later notarized writing can ever change the agreement omits New Mexico's express
course-of-conduct alternative.

What trips people up

• Acknowledgment is mandatory. New Mexico adds it to the signed-writing
  form rule.
• Spousal support cannot be waived. The state uses a substantive bar, not a
  public-assistance exception.
• Later conduct can matter. Consistent mutual conduct may amend or revoke
  the agreement even without a new writing.

Common questions

Does New Mexico require independent lawyers?

The Act does not make separate counsel a formal requirement or establish a
written counsel-waiver process. Voluntary execution and the disclosure rules
still apply to the actual circumstances.

Can the parties waive additional financial disclosure?

Yes. Section 40-3A-7(A)(2)(b) recognizes a voluntary express written waiver of
disclosure beyond what was provided. Adequate knowledge is a separate statutory
alternative within the combined defense.

What happens if the marriage is void?

Under NMSA 1978 §§ 40-3A-8-40-3A-10, an agreement that otherwise would have
been a prenup is enforceable only as necessary to avoid an inequitable result.
The remaining sections toll limitations during marriage, preserve equitable
time defenses, and direct uniform construction.

Statutes and sources

• NMSA 1978 §§ 40-3A-1 to 40-3A-10 — current New Mexico Uniform
  Premarital Agreement Act, including acknowledgment, nonwaivable subjects,
  enforcement, and later conduct. Official NMOneSource
  PDF (accessed
  2026-07-28).
• Rivera v. Rivera, 2010-NMCA-106, 149 N.M. 66, 243 P.3d 1148 — support
  waiver contrary to § 40-3A-4(B) and resulting unconscionability.
  Opinion (accessed
  2026-07-28).
• NMSA 1978 § 40-4-9.1(D) — a parental custody agreement remains subject to
  the child's best interests. Official NMOneSource
  PDF (accessed
  2026-07-28).