An Illinois petition for paternity — filed under the Illinois Parentage Act of 2015 as a Petition for Parentage — is the court filing that legally establishes who a child’s parents are and opens the door to enforceable orders for child support, parenting time, and decision-making. You complete the statewide standardized form, file it electronically through eFileIL in the circuit court of the county where the child lives, pay the filing fee or request a waiver, and arrange for the other parent to be served. Every circuit court in Illinois is required to accept the approved statewide form, which is available free on the Illinois Courts website.
Who Can File
Either parent can file. So can the child (through a representative if still a minor), a pregnant person before the child is born, a presumed or alleged parent, an intended parent under a surrogacy or assisted reproduction arrangement, and any person or agency with physical possession of, custody of, or financial responsibility for the child. The Illinois Department of Healthcare and Family Services can file if it has provided support, and child support enforcement agencies have independent standing.
Most petitions come from an unmarried mother seeking support or a father seeking parenting time, but grandparents acting as primary caregivers and adult children establishing parentage for inheritance or survivor benefits can file as well.
Deadlines
If the child has no presumed, acknowledged, or adjudicated parent, there is no deadline. A petition can be brought at any time, though once the child turns 18 only the child can initiate it.
Different rules apply when someone already holds legal parent status. To challenge a presumption created by marriage or civil union, a person other than the child must file within two years of learning the relevant facts. To challenge a Voluntary Acknowledgment of Parentage or a prior court adjudication, a non-signatory or non-party has two years from the effective date. Time spent under legal disability or duress, or during which the grounds were fraudulently concealed, does not count.
What to Gather Before You Start
Pull the following together before opening the form:
- Full legal names and current addresses for both you and the other parent. The court uses these for service and every future notice.
- The child’s full legal name, date of birth, and the county and state of birth.
- A copy of the child’s birth certificate.
- Any signed Voluntary Acknowledgment of Parentage. A VAP establishes parentage on paper but is not the same as a court judgment; the petition converts it into an enforceable order.
- Copies of any existing orders of protection, allocation judgments, or support orders involving the child or either parent.
The parentage suite on the Illinois Courts website includes separate versions labeled Mother’s Petition and Father’s Petition, a Parentage Summons, a Notice to Presumed Parent (needed when the birth parent was married at or near the time of birth), and an Affidavit of Military Service.
Completing the Petition
The person filing is the Petitioner and the other parent is the Respondent. The court tracks every motion and order under those labels, so set them correctly from the start.
The caption asks for the county, the names of both parties, and your role. Below that you enter identifying information for each party, including current county of residence. In the section about the child, fill in full name, date of birth, and county and state of birth.
A critical section asks about existing presumptions of parentage. Under Illinois law, a person is presumed to be a parent if they were married to or in a civil union with the birth parent when the child was born, or if the child was born within 300 days after that relationship ended. If any of that applies, you must also complete the Notice to Presumed Parent. If the birth parent was unmarried at and around the time of birth, that form is not needed.
If parentage is disputed, check the box asking the court to order genetic testing. When DNA testing is ordered, both parties provide samples through a chain-of-custody process and the lab sends results directly to the court. Costs may be split between the parties or covered by a fee waiver.
The last section is where you tell the court exactly what you want. Check every box that applies: establishing parentage, allocating parental responsibilities and parenting time, ordering child support, and changing the child’s name on the birth certificate. If a box is unchecked, the judge has no authority to grant that relief. Review this section carefully before submitting.
Filing Through eFileIL
Illinois requires nearly all civil filings to go through the statewide eFileIL system. Create an account at the eFileIL portal, select the county where the child resides or where the respondent can be found, and upload the completed petition with any accompanying forms.
Filing Fees
Fees vary by circuit. In St. Clair County, a Schedule 1 family filing costs $316. In Jackson County the same category is $306. Some counties charge nothing for certain parentage filings. Expect anywhere from $0 to roughly $320 depending on where you file and the exact nature of the petition.
Fee Waiver
If you cannot afford the fee, download the Application for Waiver of Court Fees from the approved forms page on the Illinois Courts website. It asks for detailed information about income, household expenses, and any government benefits you receive. An approved waiver covers the filing fee and can also cover service of process, mediation, and DNA testing later in the case.
Once the system accepts the filing, download and save the file-stamped copy immediately. You will need it to arrange service.
Serving the Other Parent
Filing alone does not give the court authority over the respondent. That comes from service of process: physically delivering the summons and a copy of the petition. The Parentage Summons must include the date the respondent is required to appear and a prominent warning that failure to appear could result in a support obligation lasting until the child is at least 18, plus liability for pregnancy and delivery costs.
Service is typically handled by the county sheriff or a licensed private process server. In Cook County the sheriff charges $60 per service for e-filed cases and $95 for paper filings. Fees in other counties generally fall between $40 and $100. After delivery, the server completes a Return of Service, which you then file with the circuit clerk.
If the respondent cannot be located for personal service, Illinois allows service by certified mail to the last known address, with the return receipt filed as proof. The clerk handles the mailing for a $1.50 fee once you provide an affidavit with the last known address. If certified mail also fails, you may need to petition the court for service by publication, which adds time and cost.
What Happens After Service
Once service is complete and filed, the court sets a hearing. What happens next depends on the respondent.
If the Respondent Agrees
If both parents appear and agree on parentage and a parenting plan, the hearing is short. You testify briefly under oath, present proof of any required parenting class, and the judge signs an Order for Parentage and Allocation of Parental Responsibilities. This can wrap up in a single court date.
If the Respondent Does Not Respond
If the respondent was properly served but does not file an answer or appear, you can ask for a default judgment. The court may adjudicate parentage against someone who is in default after service. Expect to schedule a second hearing and send the respondent a Notice of Hearing. If they still do not appear, the judge will question you under oath and may grant the petition.
If the Respondent Denies Parentage
When the biological relationship is contested, the judge orders genetic testing. After the lab report comes in, the court schedules another hearing. Results confirming parentage move the case to support and parenting time. Results excluding the alleged parent lead to dismissal.
If Parentage Is Agreed but Other Issues Are Not
Sometimes parentage itself is not in question, but the parents disagree about parenting time, decision-making, or support. The judge will likely order mediation first. If that does not produce an agreement, the case moves toward a trial on the disputed issues.
Temporary Orders While the Case Is Pending
You do not have to wait for a final judgment to get support or parenting time in place. Illinois allows temporary orders at any point during the proceeding. A temporary support order can be entered against a presumed parent, someone identified through genetic testing, an alleged parent who refused testing, or anyone shown by clear and convincing evidence to be the child’s parent. Temporary orders can also address parenting time and prohibit either parent from removing the child from Illinois while the case is pending.
What the Final Judgment Covers
The parentage judgment identifies the child by name and date of birth and adjudicates whether the alleged parent is the child’s legal parent. Beyond that finding, the judgment must address or explicitly reserve several matters:
- Child support calculated under Illinois guidelines, retroactive to the date the summons was served. Support continues until the child turns 18, or 19 if the child is still in high school.
- Parenting time and decision-making authority, either allocated in the judgment or reserved for a later proceeding.
- A change to the child’s name, if both parents request it.
- Access to group health insurance for the child through either parent.
- Ongoing reporting obligations: the non-custodial parent must notify the court and the other parent within seven days of any new employer, and both parents must report an address change within five days.
Once entered, the judgment carries the full force of a court order. Withholding support payments or denying parenting time can lead to contempt proceedings.
If You Already Signed a Voluntary Acknowledgment
A VAP signed at the hospital or later through HFS establishes parentage but does not by itself create enforceable orders for support or parenting time. Filing a petition converts the acknowledgment into a court judgment.
Either parent can rescind a VAP within 60 days of the date it was filed with HFS by completing the HFS 3416E Rescission form. Only the person who signed the particular document can rescind it: the parent who signed the VAP rescinds the VAP, and the spouse who signed a denial rescinds the denial. After 60 days, the only way to challenge a VAP is by filing a court action alleging fraud, duress, or material mistake of fact within two years.