You should speak with a lawyer if:

• The child's living situation has changed. For example, the child is now living with you or someone other than the person with the majority of parenting time
• You owe back child support
• You want to file your petition in a different judicial circuit than where your case was originally filed
• You have more than one child support order

Fill out and sign the forms listed below. Make at least 3 copies of each form.

• Petition for Modification of Child Support: This program will help you prepare the following forms:
  • Petition for Modification of Child Support
  • Certificate of Mailing of Petition for Modification of Child Support
  • Notice of Hearing
  • Child Support Information Sheet
  • Certificate of Mailing Notice of Hearing
  • Order for Support
  • Order Modifying Child Support
  • Summons: Tells the other person that a lawsuit was filed against them. 

There are fees to file many court forms, especially when starting a case. Fees are different from case to case and county to county. Contact the circuit clerk to find out about their fees. Many circuit clerks list theirs fees on their website. 

If you qualify, you can get a Fee waiver. A fee waiver allows you to file for free, or at a reduced cost.

Note: liability for child support does not require a previous court order for parental responsibilities.

Now that you have filled out your forms, you need to file them with the appropriate circuit clerk. You will need to electronically file ("e-file") them unless you have an exemption. 

Do this at the courthouse in the county where the original Child Support Order was entered. If you or the other parent does not live in the judicial circuit where the original case was filed, you may be able to file your petition in the original judicial circuit or where either of you now lives. View a map of judicial circuits on the Illinois Courts website  ​

Note: It is a good idea to talk to a lawyer if you want to file your petition in a different judicial circuit than where your case was originally filed. 

You should file the following forms:

• Petition for Modification of Child Support - an original and two copies (attach a copy of your last Child Support Order to each Petition)
• Child Support Information Sheet
• Application for Waiver of Court Fees (if applicable)

After filing, you must notify the other parent about your request to modify child support. You will need to:

• Mail a stamped copy of your Petition to the other party;
• File a Certificate of Mailing Petition for Modification of Child Support with the circuit clerk certifying the date you mailed it and the address where you mailed it; and
• Mail a stamped copy of the Certificate of Mailing to the other parent.

The other parent may waive the mail notice and agree to the terms of your Petition. If so, have the other parent sign the Entry of Appearance, Waiver, and Consent form. You can get this form from the circuit clerk's office in your courthouse.

Please note that the other parent must have seen a copy of the Petition and a copy of the Order Modifying Child Support you plan to give to the judge. The other parent's signature must be notarized. If they do not sign this form, you will need to mail it as described.

You must also send a stamped copy of the Petition for Modification of Child Support to the Illinois Department of Healthcare and Family Services (HFS) and file a Certificate of Mailing of Petition for Modification of Child Support with the court if either of the following is true:

• The person receiving child support is receiving cash assistance from HFS; or
• If the IV-D Services helped the person receiving child support get the original Order you are trying to modify.

Then you must mail a stamped copy of the Certificate of Mailing of Petition for Modification of Child Support to the HFS office.

You can check the court file or the original Child Support Order to get their current mailing address. If you cannot find this information, call the HFS' toll-free number at (800) 447-4278. 

Depending on whether you e-filed the petition or paper filed it and in which county you filed your Petition, you will need to find out the hearing date. 

How you will find out about the court date (or hearing date) and time depends on how you filed your case.

• E-filing: The website you used to electronically file may let you pick your court date (or hearing date) and time. If it does not, contact the clerk. 
• Paper filing: If you filed in person at the courthouse, the clerk will let you pick or they may pick for you.

Some counties will notify the other parent of the hearing date, but in most counties, you need to complete and send the Notice of Hearing form to the other parent. You will then need to file with the circuit clerk the Certificate of Mailing of Notice of Hearing to certify when you mailed it.

Prepare your testimony using the Petition for Modification of Child Support as your guide. You will need to testify about all of the facts in your Petition (the numbered parts of the Petition). You will also need to testify as to what you want the court to do (the lettered parts of the Petition).

If you ask the court to do something that was not in your Petition, you may have to fix your Petition.

Go to court on the date listed on your Notice of Hearing.

It is important to follow the below suggestions when going to court:

You have the right to represent yourself in court. However, you are expected to follow the court's rules and procedures. Most people who work in the courthouse cannot give you legal advice; meaning they cannot help you decide what to do, evaluate your possibility of success, or present your argument to the judge. 

To navigate the court system, you need basic information about your case. Most of the information should be listed on court papers:

• Plaintiff's or Petitioner's name
• Defendant's or Respondent's name
• Case number
• Judicial circuit
• County
• Division

If you are filing a case, you are called the plaintiff. If a case has been filed against you, you are called the defendant. In some cases, the plaintiff is called the petitioner, and the defendant is called the respondent.

Bring copies of all the documents you filed and any papers relating to what you are requesting, including your request for child support. To testify, you will need to call yourself as a witness. The judge or the judge's clerk will put you under oath, and you will present your testimony.

When you testify, your testimony should include:

1. Your name and address
2. The other party's name and children
3. The names and birth dates of the children
4. Where the children live
5. How much income the other parent has and where it comes from
6. How much income you have and where it comes from
7. What has changed since the last child support order
8. What the current support amount is and why you think it should be changed
9. How much you want the support amount to be

If the judge grants your Petition, present your Order for Modification of Child Support and Order for Support to be signed. If the judge wants corrections made, don't panic. You can ask for permission to submit a corrected version by mail.

If this is your first time going to court, learn more about the process of Going to court in Illinois.

If your Petition for Modification of Child Support is granted

After the judge has signed the Order Modifying Child Support and Order of Support, you must send a stamped copy of the Orders to the other parent. To certify (prove) that you have done this, you will need to file a Certificate of Mailing with the circuit clerk.

Like all documents you file, be sure to keep stamped copies of these documents for yourself. Remember to hold on to the Orders as they are your proof that the support has been modified. If you lose the Orders, however, don't panic. As with any document you file, you can always get another copy from the circuit clerk.

If you are the parent receiving support, you may also need to complete and file the Notice to Withhold Income for Child Support. After you have filed the Notice, mail a copy to the paying parent's employer so that the child support can be deducted from his or her paycheck.

To certify (prove) that you have done this, you will need to file an Affidavit of Service of Notice to Withhold Income for Child Support with the circuit clerk. Be sure to keep stamped copies of these documents for yourself.

If your Petition for Modification of Child Support is denied

If your request was denied because you did not have enough evidence, then you will have to wait until circumstances change before you can file another Petition. This is because once the court makes a decision about an incident or an event, it cannot address that same incident or event again.

If your request was denied because of some procedural error on your part, then you should correct the error and request another hearing.