Agreements spouses make during marriage about their property must be written and signed by both, and they are enforceable unless the spouse challenging one proves, by clear and convincing evidence, problems such as fraud, coercion, lack of full knowledge or unfairness.
Official title: postnuptial agreements; enforcement
- September 12, 2026
What changes
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NowState law defines a "postnuptial agreement" as an agreement made during marriage to divide or delineate (spell out) one or both spouses' property interests. It must be in writing, signed by both spouses, and takes effect when both have signed it.
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NowA postnuptial agreement cannot be enforced if the spouse it is used against proves any of these: it was tainted by fraud, coercion or undue influence; that spouse did not act with full knowledge of the property involved and their rights in the agreement; it is not fair and equitable; or it does not reflect a shared intent to divide or delineate property interests.
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NowThe spouse challenging a postnuptial agreement has the burden to prove it is not enforceable by "clear and convincing evidence," which generally means a high level of proof, more than "more likely than not."
BeforeThe list of what spouses may cover in an agreement (property rights, managing property, dividing property on separation, divorce or death, changing or ending spousal support, wills and trusts, life insurance death benefits, which state's law applies, and other lawful matters) applied to premarital agreements.
NowThe same list applies to postnuptial agreements, and a postnuptial agreement, like a premarital one, may not harm a child's right to support.
BeforeAfter marriage, a premarital agreement could be changed or canceled only by a written agreement signed by the parties, and the time limit for suing over a premarital agreement was paused during the marriage.
NowThese same rules now apply to postnuptial agreements: they may be changed or canceled only by a signed written agreement, and the time limit for suing over one is paused during the marriage, though defenses such as laches and estoppel are still available.
Who it affects
- Married couples who make or have made agreements about their property during marriage
- Spouses involved in divorce, separation or estate matters that involve such agreements
- Children whose right to support could be affected by such agreements
- Arizona courts that decide whether these agreements are enforceable
What you need to do
Nothing, unless you are making a postnuptial agreement; it must be in writing and signed by both spouses.
What the law doesn't answer
- Whether these rules apply to postnuptial agreements signed before the law takes effect
- How courts will decide whether an agreement is "fair and equitable"
- What counts as "full knowledge" of the property involved, such as whether a written financial disclosure is required
- Whether each spouse needs a separate lawyer
- What rules applied to postnuptial agreements before this law
This summary describes the law as enacted. Later laws, court rulings or referendum petitions can change the picture. Check the official text for the current wording.