Missouri Prenuptial Agreement Laws: Enforceability Test (2026)

Prenuptial agreements can be enforced in Missouri, but only if they pass a two-part test Missouri courts have applied to divorce-related prenups since Ferry v. Ferry, 586 S.W.2d 782 (Mo. App. 1979): the agreement must have been entered into "freely, fairly, knowingly, understandingly and in good faith with full disclosure," and it must not be unconscionable. Separately, RSMo 451.220 requires marriage contracts that affect property to be in writing and acknowledged.

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

Jurisdiction scope: This article covers the enforceability of prenuptial agreements in Missouri under Missouri Court of Appeals decisions (Ferry v. Ferry, Darr v. Darr, Miles v. Werle, King v. King and Potts v. Potts) and the formal rules in RSMo 451.220, 451.230, 474.120 and 474.220. It does not cover child support or custody terms, amendment or revocation, time limits for a challenge, or other states' law. For how Missouri divides property without an agreement, see Missouri divorce laws.

Are prenups enforceable in Missouri?

Yes, if they meet the Missouri test. In Ferry v. Ferry, the Missouri Court of Appeals held that antenuptial agreements made in contemplation of divorce are not against public policy in themselves. It also held that a court is bound by one only if it was fairly made and its terms are conscionable, drawing on the conscionability review Missouri applies to separation agreements under RSMo 452.325.

Later decisions restated the test in the same two parts. Miles v. Werle, 977 S.W.2d 297 (Mo. App. 1998), put it this way:

"In Missouri, to be valid and enforceable an ante-nuptial agreement must (1) be entered into freely, fairly, knowingly, understandingly, and in good faith with full disclosure, and (2) must not be unconscionable."

King v. King, 66 S.W.3d 28 (Mo. App. 2001), used nearly identical wording. The decisions discussed on this page come from the Missouri Court of Appeals; this page does not cover any Missouri Supreme Court ruling on prenups.

The opinions discussed here do not apply a uniform premarital agreement act. This page does not cover whether any Missouri statute beyond those named below addresses premarital agreements.

Formal requirements: writing and acknowledgment

Missouri has a statute on marriage contracts that affect property. RSMo 451.220 provides:

"All marriage contracts whereby any estate, real or personal, in this state, is intended to be secured or conveyed to any person or persons, or whereby such estate may be affected in law or equity, shall be in writing, and acknowledged by each of the contracting parties, or proved by one or more subscribing witnesses."

Under RSMo 451.220 and 451.230 together, these contracts are acknowledged the way deeds are and recorded in each county where the affected property is located. This page does not cover what happens to an agreement that is signed but not acknowledged or recorded; ask a Missouri lawyer.

Two probate statutes address waivers of a surviving spouse's rights. Under RSMo 474.220, a spouse can waive the surviving spouse's right of election only in a writing signed by the waiving spouse after full disclosure of the nature and extent of that right, and only for fair consideration. Under RSMo 474.120, intestate inheritance and other statutory rights of a surviving spouse are waived by a written contract, after full disclosure of the nature and extent of those rights, "including the nature and extent of all property interests of the parties," and for fair consideration. Either waiver may be made before or after the marriage.

Disclosure: how much is enough

Full disclosure is part of the first prong of the test, but Missouri courts do not demand perfection.

• In Darr v. Darr, 950 S.W.2d 867 (Mo. App. 1997), the court wrote that "Full disclosure does not mean absolute, strict disclosure." Disclosure of 88.2% of the husband's gross monthly income, together with the wife's exposure to his finances, was substantial disclosure.
• In Miles v. Werle, the court reversed a trial court that had refused to enforce an agreement because the assets were listed without values. It held that "lack of detail does not automatically invalidate an agreement if the disclosure which was given allowed a meaningful decision to be made."
• In King v. King, the court held that not disclosing an expectancy did not invalidate the agreement.

Do both spouses need lawyers?

Not as a strict rule. Miles v. Werle lists the signatories' access to independent counsel as one relevant factor. Where neither party had or sought counsel, the court treated the lack of counsel as relevant but not dispositive.

Counsel still matters. In Ferry, the wife's lack of legal advice was one of the facts the court weighed as a sign of overreaching. In Darr, the wife had counsel and was advised not to sign, and the agreement was upheld. A lawyer licensed in Missouri can draft or review these agreements.

When a Missouri prenup is unconscionable

The second prong asks whether the agreement is unconscionable. Potts v. Potts, 303 S.W.3d 177 (Mo. App. 2010), quoting an earlier decision, described conscionability as "protection against onesidedness, oppression or unfair surprise."

Cases on each side of the line:

Missouri courts have looked at fairness at more than one point in time. In Miles, the court checked conscionability both as of the time the agreement was made and as of the date of the dissolution. The decisions discussed here do not state a single rule on when fairness is measured.

Prenups and maintenance (alimony)

Missouri courts have refused to enforce maintenance waivers in agreements that failed the test. Ferry reversed enforcement of a maintenance release as unfair, and in Potts the Court of Appeals affirmed a maintenance award after the trial court refused to enforce the prenup. For how Missouri sets maintenance without a valid agreement, see Missouri alimony laws.

What this page does not cover

This page does not cover these common prenup questions under Missouri law:

• whether a prenup can limit child support or decide custody;
• how a prenup is amended or revoked; and
• time limits for challenging an agreement.

Postnuptial agreements are covered only in part. RSMo 474.220 and 474.120 allow waivers of a surviving spouse's election and inheritance rights before or after marriage, and RSMo 452.325 governs separation agreements made when spouses separate or divorce. This page does not cover how Missouri courts treat other agreements signed during a marriage.

Property division in Missouri without a prenup

Missouri is not a community-property state. Under RSMo 452.330.1, the court sets apart each spouse's nonmarital property and divides marital property "in such proportions as the court deems just." For more, see Missouri divorce laws.

Disclaimer: This article provides general legal information about prenuptial agreements under Missouri law (Missouri Court of Appeals decisions from Ferry v. Ferry (1979) through Potts v. Potts (2010), and RSMo 451.220, 451.230, 474.120, 474.220 and 452.330), verified on 2026-10-08. It is not legal advice and is not a template for an agreement. For advice about your situation, consult a lawyer licensed in Missouri.

Related

• Prenuptial agreement laws in every state
• Missouri divorce laws
• Missouri alimony laws

Last updated: 2026-10-08.

Frequently Asked Questions

Are prenups legally binding in Missouri?

They can be. Missouri Court of Appeals decisions from Ferry v. Ferry (1979) onward enforce a prenup only if it was entered into freely, fairly, knowingly, understandingly and in good faith with full disclosure, and is not unconscionable.

Does a Missouri prenup have to be in writing?

RSMo 451.220 requires marriage contracts affecting property in Missouri to be in writing and acknowledged by each party, or proved by one or more subscribing witnesses, and RSMo 451.230 addresses acknowledging and recording them.

Do both parties need a lawyer for a prenup in Missouri?

No strict rule requires it. Miles v. Werle (1998) treats access to independent counsel as a relevant factor, not a dispositive one.

How much financial disclosure does a Missouri prenup need?

Full disclosure is required, but Darr v. Darr (1997) held it does not mean absolute, strict disclosure, and Miles v. Werle (1998) asks whether the disclosure allowed a meaningful decision.

Can a prenup be thrown out in Missouri?

Yes. In Potts v. Potts (2010), the Court of Appeals affirmed a finding that a prenup presented the night before the wedding, giving the husband all future-generated assets, was unconscionable and unenforceable.

Can you waive inheritance rights in a Missouri prenup?

Yes, within limits. RSMo 474.220 allows a waiver of the surviving spouse's right of election before or after marriage, in a signed writing made after full disclosure of the right and for fair consideration. RSMo 474.120 covers waivers of intestate inheritance and other statutory rights, which require a written contract, full disclosure of those rights and of all the parties' property interests, and fair consideration.