Basic Guide to Illinois Prenuptial Agreements​

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2024 Basic Guide to Illinois Prenuptial Agreements


You should consider whether or not a prenuptial agreement is right for you.
An Illinois prenuptial agreement, generally, may provide for a wide variety of issues, including property rights and asset issues if a marriage ends.
However, an Illinois prenuptial agreement, generally, may not provide for potential child support or custody (allocation of parental responsibilities) arrangements.
An Illinois prenuptial agreement must be in writing and must be signed by both parties.
You should hire a lawyer to assist you in drafting the prenuptial agreement. Your spouse-to-be should hire a different lawyer who will represent their interests directly.
Next Steps: Read the additional information in the Basic Guide to Illinois Prenuptial Agreements below. If you would like additional assistance feel free to call or schedule a consultation online.

Basic Information

What is a Prenup?

A prenuptial agreement, also call a “prenup”, is a written contract which is entered into before two people are married. The prenuptial agreement is effectively a roadmap for how certain issues will be handled in the event that a marriage ends. Currently in Illinois, prenuptial agreements are governed by the Illinois Uniform Premarital Agreement Act (IUPAA), 750 ILCS 10/1, et seq.

Do I Need a Prenup?

Whether or not you need a prenup will depend on your particular circumstances but in many cases, if not most cases, a prenup is a great idea. It will clarify your thinking, and your future spouse’s thinking, on how certain issues should be settled in the event that the marriage ends. A prenup can also greatly reduce the amount of attorney’s fees that you will need to spend if your marriage, unfortunately, terminates.

The following paragraphs provide some more detailed information on Illinois prenuptial agreements. Links to additional information sources are also provided so that you can inform and educate yourself. Having said that, it is often advisable to retain an attorney to assist you in the negotiation and execution of your prenuptial agreement to make sure that it complies with the Illinois prenuptial agreement requirements and is clear and enforceable.

The Illinois Uniform Premarital Agreement Act

The Illinois Uniform Premarital Agreement Act (IUPAA), 750 ILCS 10/1, et seq. applies to any Illinois prenuptial agreement executed on or after January 1, 1990. The IUPPA defines an Illinois premarital agreement as “an agreement between prospective spouses made in contemplation of marriage and to be effective upon marriage.”

There are certain specific provisions in the IUPPA which are worth pointing out, specifically:

Must be Signed

The IUPPA, at 750 ILCS 10/3, provides that a prenuptial agreement must be both (1) in writing, and (2) signed by both parties.

Consideration not Required

Most contracts require “consideration” to be valid. Black’s Law Dictionary defines consideration as follows:

consideration n. (16c) 1. Something (such as an act, a forbearance, or a return promise) bargained for and received by a promisor from a promisee; that which motivates a person to do something, esp. to engage in a legal act. • Consideration, or a substitute such as promissory estoppel, is necessary for an agreement to be enforceable.

While the concept of consideration in contracts is interesting, we need not worry about that here. Why? Because 750 ILCS 10/3 provides that an Illinois prenuptial agreement is “enforceable without consideration.”

What can be Included in an Illinois Prenuptial Agreement

750 ILCS 10/4 provides that:

(a) Parties to a premarital agreement may contract with respect to:

(1) the rights and obligations of each of the parties in any of the property of either or both of them whenever and wherever acquired or located;

(2) the right to buy, sell, use, transfer, exchange, abandon, lease, consume, expend, assign, create a security interest in, mortgage, encumber, dispose of, or otherwise manage and control property;

(3) the disposition of property upon separation, marital dissolution, death, or the occurrence or nonoccurrence of any other event;

(4) the modification or elimination of spousal support;

(5) the making of a will, trust, or other arrangement to carry out the provisions of the agreement;

(6) the ownership rights in and disposition of the death benefit from a life insurance policy;

(7) the choice of law governing the construction of the agreement; and

(8) any other matter, including their personal rights and obligations, not in violation of public policy or a statute imposing a criminal penalty.

(b) The right of a child to support may not be adversely affected by a premarital agreement.


What Cannot Be Included in an Illinois Prenuptial Agreement

An Illinois prenuptial agreement cannot predetermine an amount of child support that will be paid in the event that the marriage ends.

Similarly, an Illinois prenuptial agreement may not predetermine issues related to the custody of, or parental responsibilities related to, any minor children of the marriage.

When is it Effective

As per 750 ILCS 10/5, a premarital agreement becomes effective upon marriage.


750 ILCS 10/7 deals with the enforcement of Illinois prenuptial agreements. It provides as follows:

§ 7. Enforcement.
(a) A premarital agreement is not enforceable if the party against whom enforcement is sought proves that:

(1) that party did not execute the agreement voluntarily; or

(2) the agreement was unconscionable when it was executed and, before execution of the agreement, that party:

(i) was not provided a fair and reasonable disclosure of the property or financial obligations of the other party;
(ii) did not voluntarily and expressly waive, in writing, any right to disclosure of the property or financial obligations of the other party beyond the disclosure provided; and
(iii) did not have, or reasonably could not have had, an adequate knowledge of the property or financial obligations of the other party.

(b) If a provision of a premarital agreement modifies or eliminates spousal support and that modification or elimination causes one party to the agreement undue hardship in light of circumstances not reasonably foreseeable at the time of the execution of the agreement, a court, notwithstanding the terms of the agreement, may require the other party to provide support to the extent necessary to avoid such hardship.

(c) An issue of unconscionability of a premarital agreement shall be decided by the court as a matter of law.


Thus, for an Illinois prenuptial agreement to be enforceable, it must be either voluntarily executed, or not unconscionable at the time it is executed. Notably, even if the prenuptial agreement is unconscionable when it was executed, it will still be enforced if:

(1) there was fair disclosure;

(2) the disclosure requirement was waived; or

(3) there was full knowledge of the financial circumstances of the other party.

And again, it bears repeating that the prenuptial agreement must be in writing and signed by both parties.


In general, when considering whether or not an Illinois prenuptial agreement is unconscionable, the court will look at “whether the agreement is one which no reasonable person would make and no honest person would accept” or whether there was “a lack of meaningful choice by one party.”

Basic Guide to Illinois Prenuptial Agreements: Next Steps

This Basic Guide to Illinois Prenuptial Agreements contains some general information on whether a prenuptial agreement could make sense for you, but it is no replacement for an individualized consultation with an attorney.

If you need help, or have questions about the information in this Basic Guide to Illinois Prenuptial Agreements, feel free to call, or schedule a free 30 minute consultation via Zoom, to speak with an attorney directly about your specific circumstances.

Basic Guide to Illinois Prenuptial Agreements

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