Kansas: Prenuptial Agreement Requirements

Requirements one by one

Kansas uses the Uniform Premarital Agreement Act

K.S.A. § 23-2401 names the Uniform Premarital Agreement Act, and K.S.A.
§ 23-2402 defines a premarital agreement as one between prospective spouses,
made in contemplation of marriage and intended to become effective upon
marriage.

The Act supplies the execution rule, permitted subjects, enforcement defenses,
support limit, void-marriage treatment, limitations tolling, and later-change
procedure.

Both parties must sign a writing

Section 23-2403 requires the agreement to be in writing and signed by both
parties. It is enforceable without consideration, so no separate payment or
property exchange is required.

Under § 23-2405, the agreement becomes effective upon marriage. Signing the
document before the wedding completes execution but does not activate the
agreement by itself.

The Act does not require notarization or witnesses

The statutory form rule is a writing signed by both parties. The Act does not
add notarization, acknowledgment, witnesses, attestation, an oath, or recording
as a general validity requirement.

A notary block may serve evidentiary or practical purposes, but it should not
be described as a condition imposed by § 23-2403.

Disclosure has waiver and knowledge alternatives

Section 23-2407(a)(2) uses the classic Uniform Act structure. The challenger
must establish execution-time unconscionability and all three listed disclosure
failures: no fair and reasonable disclosure, no voluntary express written
waiver of additional disclosure, and no actual or reasonably available adequate
knowledge.

The three disclosure failures are conjunctive. Lack of a financial schedule by
itself does not satisfy the statutory defense if a qualifying written waiver or
adequate knowledge defeats one of the required elements.

Counsel and wedding timing have no fixed statutory minimum

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

Voluntary execution remains an independent enforcement requirement. The
absence of a numerical countdown does not convert a rushed or pressured signing
into voluntary execution as a matter of law.

The second enforcement route is fully conjunctive

K.S.A. § 23-2407 creates two routes to nonenforcement. Proof that the agreement
was not executed voluntarily is sufficient by itself.

The other route requires that the agreement was unconscionable when executed
and that all three disclosure failures applied before execution. The court
decides unconscionability as a matter of law. The Act does not state a general
enforcement-time unconscionability or changed-circumstances review for every
term.

A support waiver has a public-assistance floor

K.S.A. § 23-2404(a)(4) permits modification or elimination of spousal support.
Section 23-2407(b) then creates a narrow override: if the term causes a party to
be eligible for public assistance at separation or dissolution, the court may
order enough support to avoid that eligibility.

The statute does not authorize a general fairness rewrite of every support
waiver at enforcement.

Child support and custody remain protected

Section 23-2404(b) says a prenup may not adversely affect a child's right to
support. Personal-rights terms also may not violate public policy or a criminal
statute.

Custody, residency, and parenting time remain later court decisions. Current
K.S.A. § 23-3201 requires the court to decide those matters according to the
child's best interests.

Amendment or revocation requires another signed writing

After marriage, § 23-2406 permits amendment or revocation only through a
written agreement signed by the parties. The amended agreement or revocation
is enforceable without consideration.

The section does not require notarization or repeat any additional execution
formality beyond the writing and signatures.

What trips people up

• Kansas is not a community-property state. A form should not use
  “Community Property” as though it were the Kansas statutory classification.
• The disclosure route is conjunctive. Unconscionability alone does not
  establish § 23-2407(a)(2); all three disclosure failures must also be shown.
• The support override is narrow. It reaches only enough support to avoid
  resulting public-assistance eligibility.

Common questions

Does a Kansas prenup need to be notarized?

No. K.S.A. § 23-2403 requires a writing signed by both parties but does not
require notarization or witnesses for the ordinary premarital agreement.

Can the parties waive further financial disclosure?

Yes. Section 23-2407 recognizes a voluntary and express written waiver of
disclosure beyond what was provided. Adequate knowledge is a separate statutory
alternative relevant to the combined enforcement defense.

What if the marriage is later declared void?

Under K.S.A. §§ 23-2408-23-2411, an agreement that otherwise would have been a
prenup is enforceable only as necessary to avoid an inequitable result. The same
group of sections also addresses limitations tolling, uniform construction, and
the Act's application to agreements executed on or after its effective date.
Specifically, § 23-2409 supplies the tolling rule and § 23-2411 supplies the
effective-date application rule.

Statutes and sources

• K.S.A. §§ 23-2401 to 23-2411 — current Kansas Uniform Premarital
  Agreement Act. Official Act start,
  form rule,
  permitted subjects,
  amendment,
  and enforcement
  (accessed 2026-07-28).
• K.S.A. § 23-3201 — custody, residency, and parenting time according to
  the child's best interests. Official Revisor
  text
  (accessed 2026-07-28).