Is My Prenuptial Agreement Valid in Illinois?

 Posted on February 09, 2026 in Family Law

Prenuptial agreements have become increasingly common. They can be a good tool for protecting your assets in the event of a divorce. Not all prenuptial agreements are enforceable in Illinois courts in 2026, though. An Orland Park family law attorney can review your prenuptial agreement and advise you on whether it will hold up in court.

What Makes a Prenuptial Agreement Valid in Illinois?

A valid prenup must meet specific legal requirements in the Illinois Uniform Premarital Agreement Act (750 ILCS 10):

Must Be in Writing

Verbal agreements about how you will divide property or handle finances if you divorce are not enforceable per Illinois law. Both people must sign the written prenup.

Voluntary Entry Into the Agreement

A prenuptial agreement is only valid if both people sign it willingly. If one party was forced, threatened, or pressured into signing, the agreement can be thrown out. If someone is presented with a prenuptial agreement right before the wedding without time to think about it, a court may view this as being pressured to sign.

Full Financial Disclosure

Both parties must provide complete and honest information about their assets, debts, income, and financial obligations. This is called full financial disclosure. If one person hides assets or lies about debts, the prenuptial agreement may be invalid.

Both Parties Should Have Attorneys

This doesn’t automatically make a prenup valid. Illinois law does not always require both people to have their own lawyers, but having independent legal help is strongly recommended. When both parties have their own attorneys to explain the agreement and protect their interests, it is much harder for an agreement to be unfair or for one person to sign it without understanding the terms.

What Can Make My Prenuptial Agreement Invalid?

"Unconscionable Terms"

If the results of your prenuptial agreement are extremely unfair at the time of enforcement, a court may refuse to enforce it. The classic example of unconscionability is if following the terms of the prenup would leave one spouse in need of public financial assistance.

Provisions About Child Custody or Child Support

Illinois law does not allow prenuptial agreements to determine child custody arrangements or child support obligations. Even if your prenup includes these, they are not enforceable. Courts must make decisions about children based on the best interests of the child at the time of divorce. They do not care about the agreements parents made before the child was born.

Other things like property division, spousal support, and how you will handle debts are all on the table in a prenuptial agreement.

Fraud or Misrepresentation

If your spouse committed fraud or lied about their financial situation when you signed the prenuptial agreement, you may be able to have it invalidated.

This goes beyond simple failure to explain things well. Fraud means your spouse actively deceived you about something important. If your spouse told you they had no debt when they actually owed thousands of dollars, for instance, or they claimed to earn a low salary when they actually earned much more, it could invalidate the agreement.

Can My Spouse and I Write Our Own Prenuptial Agreement?

You technically can, but it’s not a good idea. Remember that it is always advisable to have professional legal help when creating a prenup or any other legal document. If you try to write your own, you may make mistakes that invalidate it, making it useless to you if you need it.

Call a Joliet, IL Family Law Attorney Today

If you have questions about whether your prenuptial agreement is valid or how it will affect your divorce, the lawyers at The Foray Hurst Firm can help. We are members of the Black Women Lawyers' Association, Black Bar Association of Will County, Cook County Bar Association, and National Bar Association, and we bring this breadth of professional knowledge to every case.

Our firm's mission is to preserve the dignity of families in transition. We understand that divorce is difficult, and we work to protect your rights while treating you with respect throughout the process. Contact The Foray Hurst Firm at 312-702-1293 today to schedule a consultation with an Orland Park prenuptial agreement lawyer.