Oregon: Prenuptial Agreement Requirements

Requirements one by one

Oregon uses the Uniform Premarital Agreement Act

ORS 108.740 names ORS 108.700 through 108.740 the Uniform Premarital
Agreement Act. The Act defines the basic form, permitted subjects,
enforcement defenses, support override, and post-marriage change method.

The agreement needs both signatures, not extra consideration

ORS 108.705 requires a writing signed by both prospective spouses. The
agreement is enforceable without consideration, so the parties do not need to
exchange an additional payment or property merely to support the contract.

Signing is not the operative date. ORS 108.715 says the agreement becomes
effective upon marriage.

The Act does not require notarization or witnesses

The basic form in ORS 108.705 is a writing signed by both parties. The Act does
not add a notary, acknowledgment, witness, attestation, oath, or recording
condition for basic validity between them.

Separate deeds, trusts, beneficiary designations, or other instruments used to
carry out a term can have their own formalities. Those formalities do not
rewrite the Act's baseline for the premarital agreement itself.

The disclosure defense has three linked elements

Under ORS 108.725(1)(b), execution-time unconscionability alone is not the full
statutory disclosure route. The resisting party also must establish all three
listed conditions: no fair and reasonable disclosure, no voluntary express
written waiver of additional disclosure, and no actual or reasonably available
adequate knowledge of the other party's property or financial obligations.

The disclosure waiver must be voluntary, express, and in writing. The statute
does not say it must be a separate document.

Oregon has no fixed counsel or wedding countdown

The Act does not require separate counsel, a written counsel waiver, or a
minimum number of days between presentation and signing. It separately makes
involuntary execution a complete defense under ORS 108.725(1)(a).

The absence of those fixed protections does not change the separate statutory
requirement that execution be voluntary.

The statute supplies the fairness standard

There are two statutory routes to nonenforcement. The first is involuntary
execution. The second is the combined test of unconscionability when signed
plus every disclosure failure listed in ORS 108.725(1)(b).

The court decides unconscionability as a matter of law. The Act does not state a
general divorce-time changed-circumstances second look for every property term;
it instead supplies the targeted support override below.

Support can be waived, subject to a public-benefits floor

ORS 108.710 permits modification or elimination of spousal support. ORS
108.725(2) limits that freedom if the term causes a party to qualify for public
assistance or medical assistance at separation or dissolution.

In that situation, the court may require the other party to provide support,
but only to the extent necessary to avoid the resulting eligibility.

Child support and custody remain outside private control

ORS 108.710(2) says a premarital agreement may not adversely affect a child's
right to support. The Act also limits personal-rights terms to matters that do
not violate public policy or a criminal statute.

Custody remains a court decision. ORS 107.137 requires primary consideration
of the child's best interests and welfare and bars deciding the issue by
isolating one factor from the rest.

Post-marriage changes require another signed writing

Under ORS 108.720, an amendment or revocation after marriage is possible only
through a written agreement signed by both parties. Like the original prenup,
the amendment or revocation needs no consideration.

What trips people up

Disclosure failure is not a stand-alone statutory defense. On the
unconscionability route, ORS 108.725(1)(b) joins execution-time
unconscionability with all three disclosure conditions.

A support waiver is not absolute. The public- or medical-assistance
override applies at separation or dissolution even when the original waiver
was otherwise valid.

Signing and effectiveness are different dates. The document can be fully
signed before the wedding but becomes effective only when the marriage occurs.

Notarization does not replace both signatures. A notarial certificate can
help authenticate the document, but ORS 108.705 requires both parties to sign.

Common questions

What happens if the marriage is declared void?

ORS 108.730 allows the would-be prenup to be enforced only to the extent
necessary to avoid an inequitable result. It does not automatically receive the
same effect as a prenup activated by a valid marriage.

Does a limitations period run while the parties are married?

ORS 108.735 tolls an applicable limitations period during the marriage.
Equitable defenses that limit delayed enforcement, including laches and
estoppel, remain available.

Can the agreement address a will, trust, or life insurance?

Yes. ORS 108.710 expressly permits will or trust arrangements that carry out
the agreement and terms governing ownership or disposition of a life-insurance
death benefit.

Can the agreement select which state's law governs it?

Yes. ORS 108.710(1)(g) lists choice of law governing construction as a
permitted subject. Whether a selected law controls a later multistate dispute
is a separate legal question.

Statutes and sources

• ORS 108.700-108.740. Current official Uniform Premarital Agreement Act:
  form, subjects, marriage trigger, amendment, enforcement, support override,
  void marriage, limitations, and severability. Official chapter
  (accessed July 28, 2026).
• ORS 107.137. Current official custody best-interests framework. Official
  chapter
  (accessed July 28, 2026).
• 2026 Update to Volume 3. Official post-session table for changes to the
  2025 ORS volumes covering chapters 90-130; it lists no 2026 change to chapter
  107 or 108. Official update
  (accessed July 28, 2026).