Can married couples sign a postnuptial agreement in Florida? Yes, and the answer itself is straightforward. What surprises most people, though, is that postnups aren’t governed by a dedicated Florida statute the way prenuptial agreements are. Florida Statutes § 61.079, the Uniform Premarital Agreement Act, covers prenups only. Postnups operate under Florida common law, which gives courts considerably more discretion when deciding whether to enforce them.

That distinction has real consequences. A poorly drafted postnup doesn’t fail immediately, it looks fine until it’s tested in a courtroom, and by then certain procedural defects or disclosure gaps can be nearly impossible to remedy. For example, an undisclosed business valuation discovered during divorce proceedings could unravel an otherwise solid agreement. Dori Shwirtz at Divorce Harmony works directly with married couples on postnuptial agreements, and the most common issue she encounters isn’t couples who skipped getting a postnup. It’s couples who got one, believed they were protected, and then discovered gaps in disclosure or execution that made the agreement vulnerable.

By the end of this guide, you’ll understand exactly what Florida law requires, which provisions will get thrown out regardless of how well-written the rest of the document is, and what a defensible postnuptial agreement actually looks like in practice.

Can Married Couples Sign a Postnuptial Agreement in Florida? What the Law Says

Because § 61.079 doesn’t apply, there’s no single statute that lists every requirement for a valid Florida postnup. Courts instead rely on common law and, primarily, on a line of case law that starts with the Florida Supreme Court’s decision in Casto v. Casto, 508 So. 2d 330 (Fla. 1987). That decision established two independent grounds a spouse can use to challenge a postnuptial agreement: bad-faith conduct in obtaining the agreement, and unfairness combined with inadequate financial knowledge. Either ground, standing alone, is enough to void the agreement.

One statutory exception applies when a postnup includes waivers of estate rights, such as elective share or homestead rights. Florida Statutes § 732.702 governs those waivers and adds signing requirements beyond what a basic postnup needs: two subscribing witnesses and a notary acknowledgment. Couples who want estate-planning provisions in their postnup need to know this before the first draft is written, not after.

In practice, the absence of a dedicated postnup statute doesn’t make the process informal. It makes it more demanding, because courts fill the gaps with case law that often favors the spouse challenging the agreement. Every decision in drafting a postnup should be made with the Casto framework in mind.

The Four Requirements That Determine Enforceability

Written and signed by both spouses

Florida courts will not enforce an oral postnuptial agreement. The written requirement is absolute, and both spouses must sign the document. A unilateral agreement, or one where only one spouse’s signature appears, has no legal standing. Beyond the legal minimum, the formality of a written, signed agreement signals mutual consent to any court reviewing the document later.

Full and fair financial disclosure before signing

Each spouse must disclose all assets, income, liabilities, and financial interests before the agreement is executed. Concealment or understatement of a business value, retirement account balance, or debt obligation is one of the most common grounds courts use to invalidate a postnup. “Full disclosure” is not a vague standard. Courts expect a documented, itemized financial picture from both sides, and they treat gaps in that picture as evidence that the disadvantaged spouse couldn’t have made an informed decision.

Voluntariness: the pressure problem

The agreement must be entered into freely, without fraud, coercion, duress, or overreaching. Timing matters enormously here. An agreement signed during a marital crisis, under threat of separation, or while one spouse is in a vulnerable emotional state is far more likely to be challenged successfully later. Voluntariness is evaluated at the moment of signing, not in hindsight. What felt mutual at the time can look very different to a court when the surrounding circumstances are laid out.

Notarization: recommended, and sometimes statutorily required

Notarization is not a universal legal requirement for a Florida postnup to be enforceable, but it is strongly recommended as documented proof of authentic, voluntary execution. When the agreement includes real estate transfers or estate-right waivers governed by § 732.702, Florida law mandates two subscribing witnesses and a notary acknowledgment, that requirement is statutory and non-negotiable. Couples who skip notarization on a general postnup create an unnecessary vulnerability; couples who omit it on an estate-rights waiver face a more immediate problem, because that statutory requirement is mandatory, not advisory.

What a Florida Postnup Can and Cannot Include

Florida courts generally uphold postnuptial provisions that cover division of marital and separate property, including real estate, business interests, investment accounts, and personal assets. Alimony provisions are also fair game: a postnup can waive, limit, or modify spousal support, and courts will enforce those waivers if the agreement meets all other validity requirements. Debt allocation, specifying which spouse is responsible for which liabilities, is another enforceable category. Estate-rights waivers, such as elective share or homestead rights, can also be included when properly executed under § 732.702.

There are categories courts will reject regardless of how clearly they’re written. Any provision that waives or reduces child support will not survive review; the right to financial support belongs to the child, not the parents, and it cannot be eliminated by contract. Predetermined child custody or timesharing arrangements are also unenforceable, because courts must decide those issues based on the child’s best interests at the time of the proceeding, not based on what parents agreed to years earlier.

Unconscionable waivers, terms so one-sided they shock the conscience, invite challenge even when both spouses signed willingly. And one additional nuance worth knowing: Florida courts will not enforce a postnuptial waiver of temporary support or attorney’s fees during the divorce proceeding itself. Those rights exist during litigation and cannot be contracted away in advance.

How Florida Courts Decide Whether to Uphold or Overturn a Postnup

The Casto two-prong test controls the analysis. Under prong one, a court sets aside a postnup if it was obtained through fraud, deceit, duress, coercion, misrepresentation, or overreaching. This prong focuses entirely on how the agreement came to exist, not on what it says. Under prong two, a court may reject an agreement that is unfair or unreasonable when the disadvantaged spouse also lacked adequate knowledge of the other spouse’s finances. The two prongs are independent; either one is sufficient to void the agreement.

Several cases shaped how Florida courts apply these standards in practice:

• • Casto v. Casto, 508 So. 2d 330 (Fla. 1987): the Florida Supreme Court decision that established both prongs and remains the foundational reference for every postnuptial challenge in Florida.

• • Petracca v. Petracca: refined the analytical framework around fraud, overreaching, and the adequacy of financial knowledge at the time of signing.

• • Chipman v. Chipman: reinforced that unreasonableness combined with inadequate disclosure is a separate, stand-alone basis for invalidation.

• • Lashkajani v. Lashkajani: addressed how concealment of financial information creates a presumption that disadvantages the spouse defending the agreement.

An important distinction runs through all of these cases: not every unfavorable postnup fails in court. Florida courts recognize that one spouse may negotiate harder and get more. The line is crossed when unfairness combines with concealment, coercion, or a stark mismatch in financial knowledge at the time of signing. That’s precisely why full disclosure and documented voluntary execution matter so much, even when the underlying deal is legitimately lopsided.

Step-by-Step: How to Draft a Defensible Florida Postnup

Build a complete financial disclosure packet first

Before a single clause is written, both spouses should compile and exchange a complete financial picture. The disclosure inventory should cover bank and brokerage statements, retirement account balances, real estate deeds and mortgage statements, business ownership documents and valuations, tax returns for the prior two to three years, pay stubs and commission records, credit card statements, loan documents, vehicle titles, and any inheritances or trust interests. Using appraisals for real estate or business interests eliminates future disputes about what each party actually knew at the time of signing.

Use separate legal counsel and build in negotiating time-Optional

Independent counsel for each spouse is not a legal requirement in Florida, but it is an option. Each spouse’s attorney should document that they reviewed the agreement with their client, explained the consequences, and confirmed voluntary understanding before signing. Rushing the timeline is one of the most common mistakes couples make. Pressure around timing is exactly what courts look for when evaluating a challenge, and a tight turnaround between presentation and signature is difficult to explain away.

Execute with proper formalities and preserve the paper trail

Both spouses sign the final draft; a notary witnesses execution; if estate-rights clauses are included, two subscribing witnesses are required under § 732.702. Keep all drafts, disclosure packets, attorney correspondence, and signed acknowledgments together in a secure file. The paper trail is your defense if the agreement is ever challenged. A clean record of voluntary negotiation, adequate time, and full disclosure is far more persuasive to a court than a well-written agreement with no documentation of how it came to be.

Why Working with a Florida Attorney Makes All the Difference

Generic online postnuptial agreement templates are not drafted for Florida’s common-law enforceability standards. Many include prohibited provisions, like child support waivers, that trigger immediate rejection. Templates also can’t account for the specific financial disclosure requirements courts expect, or the witness and notarization formalities required for estate-rights waivers under § 732.702. A document that looks complete on its surface can fail entirely when tested against Casto, and by then there’s nothing left to fix.

Divorce Harmony, led by Dori Shwirtz, works directly with married couples to draft postnuptial agreements tailored to their specific financial situation and goals. Both spouses work with one professional who handles drafting, guides the disclosure process, and helps navigate the conversation around the agreement itself, reducing friction and coordination gaps that can create vulnerabilities later. For couples weighing whether a postnup is the right move, or wanting to understand how it would interact with a potential future divorce process, Divorce Harmony offers a free initial consultation to assess the situation before any commitment is made.

A postnuptial agreement is not something to delay when you need one. The circumstances that make a postnup valuable can shift quickly, and Florida courts evaluate the conditions at the moment of signing. Reaching out to Divorce Harmony for that initial conversation costs nothing; operating without a valid agreement when you need one can cost far more.

Can Married Couples Sign a Postnuptial Agreement in Florida? Frequently Asked Questions

Is a postnuptial agreement legally binding in Florida?

Yes. Married couples can sign a postnuptial agreement in Florida, and courts will enforce it provided the agreement is written, signed by both spouses, supported by full financial disclosure, and entered into voluntarily. Florida relies on common law, anchored by Casto v. Casto, rather than a dedicated postnup statute to evaluate enforceability.

Does a Florida postnup need to be notarized?

Not always. Notarization is strongly recommended as proof of voluntary execution, but it is only a legal requirement when the agreement includes estate-right waivers or real estate transfers governed by Florida Statutes § 732.702, which also requires two subscribing witnesses.

Can a postnup address child custody or child support in Florida?

No. Provisions that predetermine child support amounts or custody arrangements are unenforceable. Florida courts decide both issues based on the child’s best interests at the time of any proceeding, and those rights cannot be contracted away in advance.

How long does it take to finalize a Florida postnuptial agreement?

There is no mandated waiting period, but a rushed timeline is one of the most common reasons courts scrutinize a postnup closely. Building in adequate time for financial disclosure, independent legal review, and negotiation strengthens the agreement’s defensibility considerably.

Putting It All Together

Florida postnuptial agreements are legally recognized and enforceable, but they operate under common law rather than a statutory framework, and that puts the burden squarely on the drafting process. The four pillars (written, signed, fully disclosed, and voluntary) are non-negotiable. Courts fill every gap with case law that frequently favors the spouse challenging the agreement.

Provisions involving child support or custody will not survive judicial review. Unconscionable terms invite challenge regardless of how clean the rest of the agreement looks. An agreement that was rushed, undisclosed, or executed under pressure carries a structural weakness that no amount of careful drafting can fix after the fact.

So: can married couples sign a postnuptial agreement in Florida? Yes, but only a properly executed one provides genuine protection. For married couples who want a postnuptial agreement that actually holds up, working with a Florida-licensed attorney from the start isn’t optional. Contact Divorce Harmony to schedule a free consultation and find out exactly what your postnup needs to cover and what a realistic timeline looks like for your situation.