A prenuptial agreement cannot legally determine child custody, parenting time, or child support in Illinois. Any clause attempting to predetermine custody or parenting time will not bind an Illinois court, because courts must decide child-related issues based on the child’s best interests at the time those issues arise. Under the Illinois Uniform Premarital Agreement Act, a child’s right to support may not be adversely affected by a premarital agreement.
Although Illinois law does not allow prenuptial agreements to control child custody, parenting time, or child support, a properly drafted prenup can still protect significant financial interests. At Caesar & Bender, LLP, Chicago prenuptial agreement lawyers Michael Ian Bender and Molly E. Caesar help individuals and couples create enforceable prenuptial agreements that safeguard separate property, business interests, inheritances, and spousal maintenance rights while avoiding provisions that Illinois courts will not enforce.
This guide explains why Illinois law prohibits custody provisions in prenups, what the statute says, how courts decide custody, what a prenup can protect, and how to draft an agreement that holds up. Call Caesar & Bender, LLP at (312) 236-1500 to schedule a consultation.
Can a Prenup Include Child Custody Terms in Illinois?
No. A prenuptial agreement cannot create binding terms for child custody, parenting time, or child support. 750 ILCS 10/4(b) explicitly states that a premarital agreement cannot adversely affect a child’s right to support. Courts retain final authority to approve or decide child-related issues, including parental responsibilities, parenting time, and child support.
This prohibition exists because children’s rights cannot be bargained away by adults before a court can evaluate the child’s actual circumstances. A couple signing a prenup has no way to predict what custody arrangement will serve a child’s best interests years or decades later. Even if both spouses voluntarily agree to a custody clause in a prenup, that clause is not binding on the court in a divorce proceeding. The court will make its own custody determination based on the circumstances that exist at the time of divorce, not promises made before the marriage.
Key Takeaway: Illinois courts will not treat prenup custody or parenting-time terms as binding, and 750 ILCS 10/4(b) prohibits premarital agreements from adversely affecting a child’s right to support.
What Does Illinois Law Actually Say About Prenups and Children?
The Illinois Uniform Premarital Agreement Act, codified at 750 ILCS 10, governs what prenuptial agreements can and cannot do. Section 4(b) states that the right of a child to support cannot be adversely affected by a premarital agreement. This language is broad enough to cover direct waivers of child support as well as clauses that would reduce, limit, or cap what a child is entitled to receive.
The public policy rationale is straightforward. Child support must reflect the child’s needs and the parents’ financial circumstances when support is determined. A contract signed years before a child exists cannot account for that child’s health, educational needs, living situation, or relationship with each parent.
What Child-Related Provisions Are Off-Limits?
Courts will not enforce prenup clauses that attempt to limit a child’s rights or bind the court on child-related issues. The following types of provisions should not be included because they are unenforceable or subject to court approval:
- Establish a custody schedule or parenting plan in advance
- Allocate parenting time between spouses
- Waive either parent’s obligation to pay child support
- Cap the amount of child support at a predetermined figure
- Designate one parent as the primary residential parent
- Limit a court’s authority to modify custody or support in the future
These provisions are not binding on the court, regardless of how clearly they are written or how voluntarily both parties signed. No amount of careful drafting can make a custody clause binding in Illinois.
What Happens to the Rest of the Prenup If It Contains a Custody Clause?
A custody clause does not necessarily invalidate the entire prenuptial agreement. A court may be able to strike the invalid child-related clause while preserving the remaining financial terms. However, this depends on how the prenup was drafted. A well-drafted prenup includes a severability provision stating that if any single clause is found unenforceable, the remaining terms survive. Without severability language, the court may have to evaluate whether the invalid provision affects other parts of the agreement.
Key Takeaway: A severability clause can help preserve valid financial provisions even if a court refuses to enforce a child-related provision.
How Do Illinois Courts Decide Custody and Parenting Time?
When a marriage ends in Illinois, courts decide significant decision-making responsibilities under 750 ILCS 5/602.5 and parenting time under 750 ILCS 5/602.7, applying the child’s best interests. This standard applies regardless of any prior private agreement between the parties.
The court evaluates statutory best-interests factors, including:
- The wishes of the child, considering the child’s maturity
- The wishes of each parent
- The child’s adjustment to home, school, and community
- The mental and physical health of all individuals involved
- The amount of time each parent spent performing caretaking functions
- Whether there has been physical violence, threats of physical violence, abuse, or other safety concerns affecting the child or household
- The willingness of each parent to facilitate a close relationship between the child and the other parent
No single factor controls the outcome. The court weighs all relevant circumstances that exist at the time of the proceeding, not when a prenup was signed.
Child support follows a separate process. Under 750 ILCS 5/505, Illinois calculates support using guidelines that consider the parents’ combined net income, each parent’s share of that income, parenting arrangements, and the child’s needs.
Key Takeaway: When a marriage ends, the court evaluates custody using statutory best-interests factors that exist at the time of the proceeding. No prior private agreement between parents, including a prenup, can substitute for this judicial review. Child support is calculated based on both parents’ income at the time of divorce.
What Can a Prenuptial Agreement Cover?
While prenups cannot govern children, they remain one of the most effective legal tools for protecting financial interests in a divorce. Under 750 ILCS 10/4, a prenuptial agreement can address a broad range of financial and property matters.
| Subject | Can a Prenup Address This? | Notes |
|---|---|---|
| Property division | Yes | Defines separate vs. marital property |
| Spousal maintenance (alimony) | Yes | Can modify or eliminate support, subject to possible court review for undue hardship |
| Debt allocation | Yes | Protects each spouse from the other’s debts |
| Business ownership interests | Yes | Shields premarital business value |
| Inheritance and estate rights | Yes | Can waive or define rights |
| Life insurance obligations | Yes | Can require coverage amounts |
| Child custody | No | Void under 750 ILCS 10/4(b) |
| Child support | No | Cannot adversely affect child’s right to support |
| Parenting time schedule | No binding prenup term | Court must approve or decide parenting time under the best-interests standard |
Protecting Separate Property and Assets
One of the most common reasons couples sign prenups is to define what property remains separate and what becomes marital. Without a prenup, assets acquired during the marriage, and sometimes the appreciation of premarital assets, can become subject to equitable distribution in a divorce. A prenup can specify that certain real estate, investment accounts, retirement funds, income, and family heirlooms remain the property of the spouse who brought them into the marriage. For business owners in Chicago, a prenup can protect premarital business value and prevent a spouse from claiming an ownership stake in the company.
Spousal Support and Maintenance Terms
Adults can contract for themselves in ways they cannot contract for their children. A prenup can modify or eliminate spousal maintenance, cap the amount, set a duration, or establish a formula tied to the length of the marriage, subject to Illinois enforceability limits. Spousal maintenance is a right that belongs to the spouse, so it may generally be modified or limited in a prenup if the agreement is enforceable.
Key Takeaway: While prenups cannot govern children, they remain one of the most effective legal tools for protecting individual assets, defining property rights, and limiting spousal maintenance exposure in a divorce. Adults can voluntarily waive their own financial rights but cannot waive their children’s right to support.
Chicago Prenuptial Agreement Attorneys – Caesar & Bender, LLP
Michael Ian Bender, Esq.
Michael Ian Bender is a co-founding partner of Caesar & Bender, LLP and a former Domestic Relations Judge for the Circuit Court of Cook County. Drawing on decades of family law experience and thousands of cases presided over from the bench, he helps clients create prenuptial agreements designed to withstand scrutiny and protect their financial interests under Illinois law.
He earned his J.D., cum laude, and LL.M. with honors from the University of Illinois Chicago School of Law. His recognitions include Best Lawyers in America, Leading Lawyers, Lawyers of Distinction, Litigator of the Year, and Lawyer of the Year, reflecting his longstanding contributions to the field of family law.
Molly E. Caesar, Esq.
Molly E. Caesar is a co-founding partner of Caesar & Bender, LLP, whose practice includes prenuptial agreements, divorce, custody, support, and other complex family law matters. A certified mediator and experienced litigator, she helps clients negotiate and draft customized prenuptial agreements that address their unique financial circumstances while complying with Illinois law.
She graduated summa cum laude from DePaul University College of Law and was inducted into the Order of the Coif. She serves as an Adjunct Professor at DePaul University College of Law. She has been recognized by Super Lawyers as a Rising Star from 2018 through 2024 and a Super Lawyer since 2025, she has been recognized by Lawyers of Distinction and Litigation of the year, as well as various other accolades for her excellence in family law.
What Makes a Prenuptial Agreement Enforceable?
Under 750 ILCS 10, a prenuptial agreement must be written, signed by both parties, executed voluntarily, and free from unconscionability or disclosure issues. Problems with voluntariness, unconscionability, financial disclosure, or invalid provisions can give a court grounds to refuse enforcement of all or part of the agreement.
The core enforceability requirements are as follows:
- Written and signed: Oral prenups are not enforceable. The agreement must be in writing and signed by both parties.
- Voluntary execution: Both parties must sign willingly, without coercion, fraud, or undue pressure. A prenup signed the night before the wedding raises serious duress concerns.
- Financial disclosure or valid waiver: Each party should provide fair and reasonable disclosure of property and financial obligations, unless the other party validly waives further disclosure in writing and has adequate knowledge of the other party’s finances.
- No unconscionability problem: A court may refuse enforcement if the agreement was unconscionable when signed and the challenging party lacked fair disclosure, a valid written waiver, and adequate knowledge of the other party’s finances.
- No invalid provisions: Any clause addressing child custody or child support is void. A severability provision helps ensure invalid clauses do not bring down the entire agreement.
Both parties do not technically need separate attorneys, but independent legal representation for each spouse significantly strengthens enforceability. Courts are more likely to uphold an agreement when each spouse had the opportunity to consult independent counsel.
Key Takeaway: An enforceable prenup should be written and signed, voluntarily executed, supported by fair financial disclosure or a valid written waiver, and free from unconscionability problems.
Get Experienced Legal Guidance on Illinois Prenups and Child-Related Issues
While Illinois law does not allow prenuptial agreements to determine child custody, parenting time, or child support, a properly drafted prenup can still provide significant financial protection. Couples can use prenuptial agreements to define property rights, protect business interests, allocate debt, preserve inheritances, and address spousal maintenance. Understanding the limits of what a prenup can and cannot cover is essential to creating an agreement that will withstand scrutiny if a marriage ends.
Michael Ian Bender and Molly E. Caesar help individuals and couples throughout Chicago draft, review, and negotiate prenuptial agreements that comply with Illinois law. Drawing on decades of family law experience, they work closely with clients to protect assets, clarify financial expectations, and avoid provisions that could jeopardize the enforceability of the agreement.
Call Caesar & Bender, LLP at (312) 236-1500 to schedule a consultation. Our office at 150 N Michigan Ave #2130 in Chicago serves clients throughout Cook County and the surrounding Illinois communities.
Frequently Asked Questions About Prenups and Child Custody in Illinois
Can my prenup say who gets custody if we divorce?
No. Under 750 ILCS 10, a prenuptial agreement cannot include binding custody provisions. Courts retain final authority and apply the “best interests of the child” standard at the time of divorce. Any custody clause in a prenup is void and will be struck by the court.
Can a prenup waive child support in Illinois?
No. Child support is the child’s right, not the parent’s, and it cannot be waived in a prenuptial agreement. Courts determine child support at the time of divorce using the income shares guidelines under 750 ILCS 5/505. A clause attempting to waive or cap child support is void and unenforceable under Illinois law.
What happens if our prenup has a custody clause in it?
The court will not enforce the custody clause as binding. If the prenup includes a severability provision, the remaining financial terms, such as property, debt, and spousal maintenance provisions, may still survive. Without a severability clause, the invalid provision could jeopardize other parts of the agreement.
Can a prenup affect financial gifts or inheritance for our children?
A prenup is not the right instrument for this purpose. Estate planning tools, such as revocable trusts, wills, and beneficiary designations, are the proper way to create financial protections for children. An attorney can help you coordinate your prenup with an appropriate estate plan.
Does Illinois require both spouses to have separate attorneys for a prenup?
No. Illinois does not legally require independent attorneys, but having separate counsel significantly strengthens enforceability. A court is more likely to uphold a prenup when both parties had the opportunity to review the terms with their own lawyer before signing. Independent representation helps establish that both parties understood what they were agreeing to.
Can we modify or cancel a prenup after we are married?
Yes. After marriage, Illinois law allows spouses to amend or revoke a premarital agreement only through a written agreement signed by both parties. The amended agreement or revocation is enforceable without consideration.
Is a prenup still worth it if it cannot cover custody?
Yes. A prenup can still protect separate property, business interests, inheritance rights, and retirement accounts. It can waive or limit spousal maintenance, allocate debt responsibility, and prevent costly property disputes that would otherwise be resolved through litigation.
