Getting married in Illinois?
A prenuptial agreement lets you set clear expectations about property, debt, and (where allowed) support—so you’re not relying only on default state rules. In short: 750 ILCS 10/7 covers enforceability, including the clause about undue hardship for spousal support waivers. In In re Marriage of Barnes (Ill. App.
Key points
- Prenups are recognized if they’re voluntary, in writing, and signed by both partners.
- Illinois law (750 ILCS 10/7) states that a premarital agreement will not be enforceable if the party against whom enforcement is sought proves that (1) they did…
- Illinois enacted the Illinois Uniform Premarital Agreement Act (750 ILCS 10/1 et seq.) effective in 1990.
Illinois’s Undue Hardship Standard for Maintenance Waivers
Illinois allows spouses to waive or limit maintenance in a prenuptial agreement, but courts retain the authority to review those terms at enforcement. If enforcing a maintenance waiver would cause undue hardship due to circumstances that were not reasonably foreseeable when the agreement was signed, a court may modify or decline to enforce that provision.
This makes Illinois prenups more outcome-sensitive than in some states, particularly in long marriages or where health or earning capacity changes significantly.
Are prenups legal in Illinois?
Illinois enacted the Illinois Uniform Premarital Agreement Act (750 ILCS 10/1 et seq.) effective in 1990. A prenup in Illinois must be in writing and signed by both parties. No notarization or witnesses are explicitly required by statute, but notarization is routinely done. The marriage itself is sufficient consideration for the agreement (meaning the prenup is valid once the marriage happens).
Marriage as Legal Consideration in Illinois Prenups
Under Illinois law, the marriage itself is sufficient legal consideration for a prenuptial agreement. This means a prenup becomes enforceable once the marriage occurs, even if no additional exchange of value is listed in the agreement.
This simplifies drafting but increases the importance of disclosure and voluntariness at signing.
What makes a Illinois prenup enforceable?
Illinois law (750 ILCS 10/7) states that a premarital agreement will not be enforceable if the party against whom enforcement is sought proves that (1) they did not execute the agreement voluntarily, or (2) the agreement was unconscionable when executed and before execution that party was not provided a fair and reasonable disclosure of the other’s property and financial obligations, and did not waive the right to did not voluntarily and expressly waive, in writing, any right to disclosure beyond the disclosure provided.
How Illinois Courts Evaluate Fairness
Illinois courts generally assess fairness based on the circumstances at the time the prenuptial agreement was signed. An agreement does not need to produce equal outcomes to be enforceable, but it must not be unconscionable when executed.
Clear disclosure and informed consent often carry more weight than whether the agreement later feels imbalanced.
What you can—and can’t—include in an Illinois Prenup
Illinois permits prenups to cover property division (overriding Illinois’ default equitable distribution rules), maintenance (alimony) terms, and any other personal rights not violating public policy or criminal law. By statute, child support cannot be “adversely affected” by a prenup (750 ILCS 10/4), so any attempt to limit or waive child support is void.
Modifying an Illinois Prenup After Marriage
Illinois allows spouses to amend or revoke a prenuptial agreement after marriage, but any modification must be in writing and signed by both parties. Courts expect the same level of disclosure and voluntariness as with the original agreement.
Simple process
In Illinois, as elsewhere, early planning and full disclosure are keys to an ironclad prenup. Each party should ideally have their own attorney – in fact, many Illinois judges take the presence of independent counsel as a strong sign that the agreement was knowing and voluntary.
Independent Counsel as an Enforceability Signal in Illinois
While Illinois law does not require separate attorneys for each party, judges often view independent legal counsel as strong evidence that a prenup was entered into knowingly and voluntarily.
Next steps
General information only, not legal advice. Laws and cases change—consider speaking with a local attorney about your situation.
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