Florida Postnuptial Agreement Attorney

By Nadia Pazos, Family Law Attorney · Coral Gables, Florida · Updated August 3, 2026

Why § 61.079 Does Not Govern Your Postnuptial Agreement

This is the single most misunderstood point about postnuptial agreements in Florida, and getting it wrong changes how an agreement should be drafted.

Florida adopted the Uniform Premarital Agreement Act at Fla. Stat. § 61.079. By its own terms, that statute governs agreements made in contemplation of marriage and effective upon marriage. A postnuptial agreement is signed by people who are already married, so it falls outside the statute entirely.

The practical consequence: the statutory checklist that protects a prenup does not automatically protect a postnup. Instead, Florida courts apply general contract principles together with the standards the Florida Supreme Court set out in Casto v. Casto, 508 So. 2d 330 (Fla. 1987). Many form agreements sold online recite § 61.079 language on a postnup. That does not make the statute apply, and it can signal to a court that the drafting was careless.

What a Florida Postnuptial Agreement Can Cover

Spouses have broad freedom to contract about their financial relationship. A well-drafted Florida postnup commonly addresses:

• Classification of property — identifying what each spouse treats as separate and what is marital, which matters because § 61.075 equitable distribution otherwise decides it
• A business or professional practice — particularly one started or grown during the marriage
• Debt allocation — including student loans, business debt, and liabilities one spouse brought in
• Spousal support — waiving, capping, or defining alimony rather than leaving it to § 61.08
• The marital home — who keeps it, how equity is credited, and what happens to the mortgage
• Inheritances and gifts — confirming they remain separate even if commingled
• Estate rights — coordinating with wills, trusts, and elective share planning

What a Postnuptial Agreement Cannot Do

The limit is the same one that applies to prenups, and it is absolute: a postnuptial agreement cannot adversely affect a child’s right to support. That right belongs to the child, not to the parents. Florida courts will disregard any provision that waives, caps, or reduces child support, no matter how clearly both spouses agreed to it. Support is calculated under § 61.30 using the guidelines in effect at the time of the case.

Time-sharing and parental responsibility are likewise decided under § 61.13 according to the best interests of the child when the issue arises. Parents cannot bind a court in advance.

When a Florida Court Will Set a Postnuptial Agreement Aside

Under Casto v. Casto, 508 So. 2d 330 (Fla. 1987), a spouse can challenge a marital agreement on either of two grounds:

• Fraud, deceit, duress, coercion, misrepresentation, or overreaching. This looks at how the agreement came about — pressure, concealment, or one spouse taking unfair advantage of the other.
• The agreement is unfair or unreasonable given the parties’ circumstances. If the challenging spouse establishes this, Florida law raises a presumption that assets were concealed, and the burden shifts to the spouse defending the agreement to show either that there was full and fair disclosure, or that the challenging spouse had a general knowledge of the marital property.

That burden-shifting rule is why disclosure is the centerpiece of a defensible postnup. An agreement that is generous on its face rarely gets challenged successfully; an agreement that is lopsided and was signed without a financial disclosure schedule is exposed.

Why Disclosure Matters More After the Wedding

Engaged people are negotiating at arm’s length. Married spouses are not — they share accounts, tax returns, and financial control, and courts recognize that one spouse often has far better information than the other. A postnuptial agreement signed without a written schedule of assets, debts, and income invites exactly the presumption described in Casto.

In practice, the agreements that hold up share four traits: a complete written disclosure exchanged before signing, independent counsel for each spouse, enough time between presentation and signature to show the decision was unhurried, and terms that leave the less-monied spouse in a position a court would not call unconscionable.

Common Reasons South Florida Couples Sign a Postnup

Postnuptial agreements are rarely about expecting divorce. The most common reasons in Miami-Dade, Broward, and Palm Beach counties are:

• One spouse launched or acquired a business during the marriage and partners or lenders want the ownership clarified
• An inheritance or family gift arrived and the couple wants it confirmed as separate property
• The couple intended to sign a prenup but ran out of time before the wedding
• One spouse is leaving the workforce to raise children and wants support terms defined now
• A blended family wants to protect children from a prior relationship
• The couple is reconciling after a separation and wants terms in writing as part of moving forward
• Significant debt — business, medical, or student — needs to be allocated

Postnuptial vs. Prenuptial: What Actually Differs

Both documents do similar work. The differences that matter are legal, not cosmetic:

• Governing law. A prenup is governed by § 61.079. A postnup is governed by common law and Casto.
• Consideration. A prenup is enforceable without separate consideration — the marriage itself supplies it. A postnup is an ordinary contract between married people, so it needs consideration; mutual waivers of rights typically supply it, which is one reason a one-sided postnup is riskier than a one-sided prenup.
• Scrutiny of disclosure. Courts examine disclosure closely in both, but the existing marital relationship makes it a sharper issue in a postnup.
• Timing pressure. A prenup carries the “signed days before the wedding” risk. A postnup has no deadline, which removes one of the most common voluntariness attacks.

If you have not married yet, see our Florida prenuptial agreement attorney page and the plain-language guide to Fla. Stat. § 61.079.

How the Process Works

A straightforward postnuptial agreement generally moves through five steps over two to four weeks:

• Consultation — what you want the agreement to accomplish and whether a postnup is the right instrument
• Financial disclosure — both spouses prepare written schedules of assets, debts, and income
• Drafting — terms are prepared and reviewed with you before anything goes to the other spouse
• Independent review — the other spouse’s attorney reviews and negotiates
• Execution — signed, witnessed, and notarized, with the disclosure schedules attached and retained

Frequently Asked Questions

Is a postnuptial agreement legally valid in Florida?

Yes. Florida recognizes postnuptial agreements between spouses. They are enforced under contract law and the standards in Casto v. Casto, 508 So. 2d 330 (Fla. 1987) rather than under § 61.079, which governs only premarital agreements.

Can a postnuptial agreement waive alimony in Florida?

Spouses may address spousal support by contract rather than leaving it to § 61.08. Whether a particular waiver is enforced depends on how the agreement was made and whether it is unfair or unreasonable under Casto. A waiver that leaves one spouse destitute is far more vulnerable than one that provides a defined, negotiated amount.

Do we each need our own attorney?

Florida does not require it, but independent counsel for each spouse is the strongest evidence that signing was voluntary and informed, and it substantially reduces the risk of a later challenge. One attorney cannot ethically represent both spouses.

Can a postnuptial agreement decide child custody or support?

No. Child support is governed by § 61.30 and belongs to the child; time-sharing is decided under § 61.13 based on the child’s best interests at the time of the case. Neither can be bargained away in advance.

Can we change or cancel a postnuptial agreement later?

Yes. Spouses may amend or revoke a postnuptial agreement by a later written agreement signed by both of them. Oral modifications are not reliable and should not be relied on.

How much does a postnuptial agreement cost in Florida?

Cost depends on the complexity of the assets involved — a straightforward agreement between two W-2 earners is very different from one involving a closely held business requiring valuation. We quote after the initial consultation, once the scope is clear.

Talk to a Florida Postnuptial Agreement Attorney

Pazos Law Group drafts, reviews, and litigates marital agreements throughout Miami-Dade, Broward, and Palm Beach counties, in English and Spanish. Whether you are proposing a postnuptial agreement, have been handed one to sign, or need to challenge one, we can tell you where it stands under Casto before you commit.

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This page is general legal information, not legal advice, and does not create an attorney-client relationship with Pazos Law Group. Florida law and the application of statutes and case law change over time; please consult a licensed Florida attorney about your specific situation.