Do I Need a Lawyer for Child Support in Illinois?

HFS child support services and private cases

Illinois has two main paths to a child support order.

• HFS Child Support Services. The Illinois Department of Healthcare and Family Services (HFS) can help parents establish parentage, establish child support or medical support and enforce support. You can apply online or call 1-800-447-4278. HFS reviews support orders in its cases for modification every three years.
• A private court case. A parent can ask a judge for support on its own or as part of a divorce, parentage or custody case. In Cook County, these cases are heard by the Domestic Relations Division.

The key difference is representation. HFS says its Child Support Services attorney does not represent either parent. A private lawyer represents you and your position.

Both paths use the same law. Illinois follows the income shares guidelines in 750 ILCS 5/505. The court determines each parent's monthly net income, adds them together, finds the basic obligation in the HFS schedule for that income and number of children, and splits it between the parents according to each parent's percentage share of the combined income. The guideline amount is presumed correct. A judge who departs from it must make written findings explaining why.

When a lawyer helps

Two parents paid by regular wages, with one main household and no disputes, may not need a lawyer. These situations usually benefit from one.

Self-employed or hidden income

For business owners, section 505(a)(3.1) defines net business income as gross receipts minus ordinary and necessary business expenses. It excludes accelerated depreciation and expenses found to be inappropriate or excessive, and it addresses in-kind payments such as a company car. When a parent is voluntarily unemployed or underemployed, section 505(a)(3.2a) lets the court base support on potential income. Under section 505(a)(3.2b), the court can impute income only after an evidentiary hearing or by agreement. A lawyer uses tax returns, bank records, subpoenas and discovery to show the real numbers.

Shared parenting time adjustments

When each parent has the child for 146 or more overnights a year, Illinois uses a shared physical care calculation (section 505(a)(3.8)). The basic obligation is multiplied by 1.5, each parent's share is figured, and the amounts are offset. Beginning January 1, 2027, Public Act 104-0733 lowers that threshold to 110 overnights or overnight equivalents. It also adds an adjustment for parents with 110 to 145 overnights. A dispute about the real parenting calendar can change the result, so it is worth getting right. See our guide to the 2026 and 2027 child support rules.

Extracurricular, childcare and health insurance add-ons

Beyond the basic obligation, the court may order parents to share reasonable school and extracurricular expenses (section 505(a)(3.6)) and reasonable child care expenses (section 505(a)(3.7)). The court must also provide for the child's health care needs, which can include health insurance and a share of uninsured medical, dental, orthodontic and vision costs (section 505(a)(4)). Add-ons are often where agreements fall apart, and they are easy to leave out.

A lawyer is also a good idea when support is tied to other disputes, such as a divorce with property and maintenance issues, a custody case, a parent in another state or a parent who has a lawyer.

Starting a support case in Cook County

1. Choose the path: an HFS application or a petition in circuit court. If you are divorcing or in a parentage case, support is usually requested in that case.
2. File in the Domestic Relations Division at the Daley Center through the Clerk's e-filing system.
3. Complete the statewide Financial Affidavit (Family and Divorce Cases). Attach supporting documents such as tax returns, pay stubs and bank statements.
4. Serve the other parent and attend the court dates the judge sets.
5. The court applies the guidelines, decides any add-on expenses and enters an order for support. Payments are often collected by income withholding.

In a pending divorce, you can ask for temporary child support while the case continues (750 ILCS 5/501). Support for a child usually ends at emancipation. If the child is 18 and still in high school, support ends at graduation or age 19, whichever comes first, unless the law, the judgment or a written agreement provides otherwise (750 ILCS 5/510(d)). Separate rules can apply to college expenses and to an adult child with a disability. See when child support ends in Illinois.

Our guide on how to get child support in Illinois covers the starting steps in more detail.

Modifying or enforcing an existing order

Modifying. Under 750 ILCS 5/510(a), an order can be modified on a substantial change in circumstances. In HFS cases, it can also be modified after 36 months when the guideline amount differs from the existing order by at least 20 percent. A modification applies only to payments that come due after the other parent receives notice of the filing, so file promptly. Read how to modify child support in Illinois.

Enforcing. If support is not being paid, options include income withholding and a petition for rule to show cause asking the court to hold the other parent in contempt. When the court finds that the failure to pay was without compelling cause or justification, section 508(b) requires the non-paying parent to pay the other parent's reasonable attorney fees for the enforcement case. A pending petition to modify does not delay enforcement (section 510(f)). See how to enforce a child support order and our court order enforcement page.

What to bring and mistakes to avoid

What to bring

• Recent pay stubs and the last few years of tax returns, with all schedules.
• Business records if either parent is self-employed.
• Any existing support or parenting orders and your HFS case number, if you have one.
• A parenting calendar showing actual overnights.
• Receipts for child care, activities, insurance premiums and medical costs.

Mistakes to avoid

• Stopping or reducing payments without a court order.
• Treating an online calculator result as if it were an order.
• Agreeing to a number without addressing add-ons and health insurance.
• Waiting to file after a job loss or a pay raise, since changes usually start only after notice.
• Making side agreements that never become a court order.
• Assuming the 2027 shared-care change rewrites your order automatically. A court process is still needed.

How the firm handles child support cases

Chicago Family Attorneys, LLC practices only Illinois family law and handles child support cases in Cook, DuPage, Will and Lake Counties. Our Chicago child support lawyers help with:

• Petitions to set support in divorce and parentage cases.
• Review of HFS calculations and proposed orders.
• Income questions, including self-employment and imputed income.
• Shared-care calculations and parenting calendar disputes.
• Add-on expenses, health insurance and child care.
• Modifications and responses to modification requests.
• Enforcement, including petitions for rule to show cause.

For full representation to set or modify child support, the usual fee is an initial payment of $1,500 to $2,500, then $500 to $650 per month beginning 30 days after the initial payment while representation remains active. Limited-scope help is a flat fee for a defined task: drafting a motion for you to file starts at $500, and appearing for you at one hearing starts at $1,200. Enforcement of an existing order is billed under the firm's separate court order enforcement fee structure. See child support lawyer fees and our child support tools. No lawyer can promise a particular support amount.