Prenuptial Agreements in Illinois

A prenuptial agreement is a legal document drawn up between two people who intend to marry. The plans they draw up become enforceable once they’re married. In Illinois, it’s very difficult to change those plans after you say, “I do.” 

Are prenuptial agreements enforcement in Illinois? 

Properly written and signed prenuptial agreements are enforceable in Illinois. If you craft a plan with your soon-to-be spouse and sign it before you get married, it becomes enforceable on your wedding day. 

Exceptions do exist. For example, if you can prove that your prenuptial agreement was forced on you, a court could side with you and throw the document out. 

But in most cases, prenuptial agreements are enforceable in Illinois. Be careful before you sign these documents, as it’s difficult to change your plans later.

Illinois prenuptial agreement law 

People preparing prenuptial agreements in Illinois should become familiar with the Illinois Premarital Agreement Act. Everything you need to know about what you can (and can’t) put into these documents is included within the act. 

Here’s what you should know:

What can an Illinois prenup include? 

You can put plenty of information in a prenuptial agreement in Illinois. The Illinois Premarital Agreement Act says you can spell out the following details inside your documents:

  • Property ownership
  • Spousal support 
  • Wills or trusts to carry out the details inside the prenup 
  • Life insurance benefits 
  • Personal rights and obligations (as long as they don’t break local laws) 

This list is long. You can use your Illinois prenup to outline almost everything about what you own now, what you plan to own as a couple, and how you want the agreement enforced. 

What can’t an Illinois prenup include?

Like most states, Illinois has tight restrictions on child support and prenuptial agreements. You can’t make arrangements that would deprive one party of the funds they will need to raise any children you might share. 

You also can’t include clauses that violate the law. Your plans must comply with local laws. 

What could invalidate a prenup in Illinois?

Once your prenuptial agreement is signed and your wedding is complete, your prenup is a valid document. But a few issues could void the arrangements you’ve made.

To invalidate your Illinois prenup, you must provide proof of the following:

  • One person forced the other to sign. 
  • One side hid assets, downplayed the hardships the other side could face, or otherwise blurred reasons one person might cite for not signing the agreement. 
  • The marriage was invalid

How long do prenups last? 

Prenuptial agreements last until both parties agree to dissolve them. In other words, they begin on the day you’re married, and they last until one of you dies. 

You could place a clause inside your prenuptial agreement that ends it early. For example, you could opt to dissolve the arrangement when you’ve been married for five or 10 years. But this isn’t required. 

These markers generally note that wealth becomes shared after a set length of time. For example, the couple may start the marriage in very different financial positions, but after a long period (often 10 to 20 years), that wealth is more shared, and financial positions are more equal. That being said, many prenuptial agreements don’t feature a sunset clause like this.  

How much do they cost?

Illinois laws don’t cap prenuptial agreement costs. You could work up your own version and pay nothing. Or, you could hire a lawyer to work with you on the document and pay hundreds or more.

What to know before signing a prenup in Illinois

Prenup agreements in Illinois are relatively easy to create, but you should consider these possibilities before you sign one:  

You may not need it 

Fewer Illinois residents are getting divorced. In 2012, more than 31,000 people split. In 2017, about 24,000 did so. 

A prenup agreement could mean starting your marriage with some level of friction. Prepare to explain your reasons for the document so your future partner doesn’t get upset. 

Your life may change 

Prenup agreements last the length of your marriage, even if your life changes. 

For example, you might have similar assets and earning power when you get married, so you might agree to a 50/50 split in your prenup. But during the marriage, what if you become injured and can’t work in your preferred industry? A wage gap widens. Upon divorce, you could regret those plans. 

Reviews can be helpful 

Few people have law degrees. If you’re not one of them, you could miss important details that invalidate your prenuptial agreement. Asking for a pro’s help could be a wise step to make sure the document is legal and fair. 

Prenup alternatives in Illinois

You’re not required to sign a prenuptial agreement. If you’re absolutely opposed to it, you might decide to cohabitate with your partner without getting married at all. If you were to also keep your finances separate, this could be quite a safe option. 

You could meet with an estate planning attorney before your wedding. A professional like this could help you set up trusts to protect your assets. You could also draft a will to protect your heirs upon your death. 

If your intended spouse wants a prenup and you do not, know this: You can’t be pressured into signing. Documents you sign under duress aren’t legally enforceable, though the person under duress would have to be able to prove they were forced to participate.

Read: Prenuptial vs. Postnuptial Agreements

Think hard about your future life together. If your partner isn’t listening to your concerns, is that a sign that the partnership won’t last? The divorce rate is significant, but some people do make it. In the eyes of many, a prenup is a logical step to take based on the fact that the divorce rate hovers around 40%.

Want to learn more about prenups, postnups, and marriage/divorce in general? We invite you to keep reading the many resources available on our website and schedule a free 15-minute phone call with an account coordinator if you’re so inclined.


2017 Divorces and Annulments Occurring in Illinois by County of Residence. Illinois Department of Public Health. 
Illinois Compiled Statutes: Illinois Uniform Premarital Agreement Act. Illinois General Assembly. 
What Is a Prenuptial Agreement? The American College of Trust and Estate Counsel.
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