How to File a Workers' Compensation Claim in Illinois
Reviewed by DocDraft Legal Team · Illinois · Last updated 2026-09-07
A workers' compensation claim is how an employee who is injured on the job, or made ill by work, obtains medical care and wage-replacement benefits from the employer's insurer, without having to prove the employer was at fault. In Illinois, the system is administered by the Illinois Workers' Compensation Commission (IWCC), which resolves disputes between employees and employers. Two deadlines are critical. You must notify your employer of the accident as soon as practicable, but no later than 45 days after it (820 ILCS 305/6), and you must file your claim with the IWCC within three years of the accident, or two years from the last payment of compensation, whichever is later (820 ILCS 305/6). Notice may be oral or written, though a dated written record is safer. If your employer or its insurer denies, delays, or underpays benefits, you open a contested case by filing an Application for Adjustment of Claim (Form IC01) with the IWCC through its CompFile system. An arbitrator hears the case, and a panel of three commissioners can review the decision. Attorney review of your claim is available through DocDraft.
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How do I file a workers' compensation claim in Illinois?
First, notify your employer of the accident as soon as practicable, and no later than 45 days after it (820 ILCS 305/6). If the injury is disputed or unpaid, file an Application for Adjustment of Claim (Form IC01) with the Illinois Workers' Compensation Commission through its CompFile system to open a case.
How long do I have to file a workers' compensation claim in Illinois?
Two deadlines matter. You must notify your employer within 45 days of the accident (820 ILCS 305/6). Separately, you must file your application with the Illinois Workers' Compensation Commission within three years of the accident, or two years from the last compensation payment, whichever is later. Missing either can bar benefits.
What is the Application for Adjustment of Claim in Illinois?
The Application for Adjustment of Claim (Form IC01) is the document that formally opens your case before the Illinois Workers' Compensation Commission. You file it through the Commission's CompFile system when your employer or its insurer denies, delays, or underpays benefits. Filing it starts the dispute-resolution process before an arbitrator.
Who handles workers' compensation claims in Illinois?
The Illinois Workers' Compensation Commission (IWCC) administers the state's workers' compensation system and resolves disputes between employees and employers. Day to day, your employer's insurer decides whether to pay benefits. If a dispute arises, an IWCC arbitrator hears the case, and a panel of three commissioners can review that decision.
Illinois workers' compensation claim law at a glance
In Illinois, workers' compensation gives an employee who is injured on the job medical care and wage-replacement benefits from the employer's insurer, regardless of fault. The system is administered by the Illinois Workers' Compensation Commission (IWCC), which resolves disputes between employees and employers. You must notify your employer of the accident as soon as practicable, but no later than 45 days after it, under 820 ILCS 305/6. Notice may be oral or written and should state the approximate date and place. If the claim is denied, delayed, or underpaid, you open a case by filing an Application for Adjustment of Claim (Form IC01) with the IWCC through its CompFile system. You must file within three years of the accident, or two years from the last payment of compensation, whichever is later (820 ILCS 305/6).
Filing an Illinois workers' compensation claim after a warehouse back injury
Suppose you hurt your back lifting boxes at an Illinois warehouse. You tell your supervisor and, that same week, put the report in writing, staying well inside the 45-day notice window (820 ILCS 305/6). Your employer's insurer starts paying for medical treatment but later disputes how much wage-replacement you are owed. Because you must act within three years of the accident, or two years from the last payment of compensation, whichever is later (820 ILCS 305/6), you file an Application for Adjustment of Claim (Form IC01) with the Illinois Workers' Compensation Commission through CompFile. An arbitrator hears the dispute. Attorney review of your claim is available through DocDraft.
Relevant Laws
820 ILCS 305/6 (45-day notice of accident to employer)
Provides that notice of the accident shall be given to the employer as soon as practicable, but not later than 45 days after the accident. The notice may be oral or written and should state the approximate date and place of the accident.
820 ILCS 305/6 (three-year / two-year limitation to file the application)
Bars the right to file unless the application for compensation is filed with the Commission within 3 years after the date of the accident, where no compensation has been paid, or within 2 years after the date of the last payment of compensation, where any has been paid, whichever is later.
Illinois Workers' Compensation Commission (administers the Act and resolves disputes)
The IWCC resolves disputes between employees and employers regarding work-related injuries and illnesses. A case is first tried by an arbitrator, whose decision may be reviewed by a panel of three commissioners, and may then be appealed to the circuit court, Appellate Court, and Illinois Supreme Court.
Regional Variances
Illinois workers' compensation claim rules at a glance
Reporting deadline
Notice of the accident must be given to the employer as soon as practicable, but no later than 45 days after the accident, under 820 ILCS 305/6. Notice may be oral or written; late reporting can jeopardize benefits.
Claim form
The Application for Adjustment of Claim (Form IC01), which the worker files with the Illinois Workers' Compensation Commission through its CompFile electronic system to open a contested case.
Filing deadline
Three years from the date of the accident where no compensation has been paid, or two years from the last payment of compensation where any has been paid, whichever is later (820 ILCS 305/6).
Who administers it
The Illinois Workers' Compensation Commission (IWCC), which resolves disputes between employees and employers. Cases are tried by an arbitrator and may be reviewed by a panel of three commissioners.
How disputes are filed
By filing an Application for Adjustment of Claim with the IWCC through CompFile when the insurer denies, delays, or underpays the claim. This must occur within the three-year or two-year limitation period.
Suggested Compliance Checklist
Report the accident to your employer
Within 45 days of the accident days after startingGive your employer notice of the accident as soon as practicable, and no later than 45 days after it (820 ILCS 305/6). Notice may be oral or written, but a dated written record is safer. Reporting late can jeopardize your right to benefits, so do this immediately.
Put your report in writing and keep proof
As soon as you report days after startingConfirm your report in writing, naming the date, place, and nature of the accident, and keep a dated copy. A written record protects you if your employer or its insurer later disputes when or whether you gave notice.
Get medical care and keep records
Ongoing after the injury days after startingSeek treatment for your injury and keep every medical record, bill, and letter from the insurer. Documenting the diagnosis, treatment dates, and any work restrictions supports your claim if benefits are later contested.
Prepare the Application for Adjustment of Claim
If benefits are denied, delayed, or underpaid days after startingComplete the Application for Adjustment of Claim (Form IC01), describing the accident, your injury, and the benefits you seek. This is the official document that opens a contested case before the IWCC. Attorney review of your claim is available through DocDraft.
File the application with the IWCC through CompFile
Within three years of the accident (or two years of last payment) days after startingFile the Application for Adjustment of Claim with the Illinois Workers' Compensation Commission through CompFile within three years of the accident, or two years from the last payment of compensation, whichever is later (820 ILCS 305/6). File early and keep your confirmation.
Track both deadlines and the case
While the claim is pending days after startingCalendar the 45-day reporting deadline and the three-year filing deadline, and note the accident date. Keep proof of your notice and filing so you can protect the limitation period under 820 ILCS 305/6 if the insurer contests the claim.
| Task | Description | Document | Days after starting |
|---|---|---|---|
| Report the accident to your employer | Give your employer notice of the accident as soon as practicable, and no later than 45 days after it (820 ILCS 305/6). Notice may be oral or written, but a dated written record is safer. Reporting late can jeopardize your right to benefits, so do this immediately. | - | Within 45 days of the accident |
| Put your report in writing and keep proof | Confirm your report in writing, naming the date, place, and nature of the accident, and keep a dated copy. A written record protects you if your employer or its insurer later disputes when or whether you gave notice. | - | As soon as you report |
| Get medical care and keep records | Seek treatment for your injury and keep every medical record, bill, and letter from the insurer. Documenting the diagnosis, treatment dates, and any work restrictions supports your claim if benefits are later contested. | - | Ongoing after the injury |
| Prepare the Application for Adjustment of Claim | Complete the Application for Adjustment of Claim (Form IC01), describing the accident, your injury, and the benefits you seek. This is the official document that opens a contested case before the IWCC. Attorney review of your claim is available through DocDraft. | - | If benefits are denied, delayed, or underpaid |
| File the application with the IWCC through CompFile | File the Application for Adjustment of Claim with the Illinois Workers' Compensation Commission through CompFile within three years of the accident, or two years from the last payment of compensation, whichever is later (820 ILCS 305/6). File early and keep your confirmation. | - | Within three years of the accident (or two years of last payment) |
| Track both deadlines and the case | Calendar the 45-day reporting deadline and the three-year filing deadline, and note the accident date. Keep proof of your notice and filing so you can protect the limitation period under 820 ILCS 305/6 if the insurer contests the claim. | - | While the claim is pending |
Frequently Asked Questions
A workers' compensation claim is how an employee injured on the job, or made sick by work, obtains medical care and wage-replacement benefits from the employer's insurer, without proving fault. In Illinois, you preserve the claim by notifying your employer, and disputes are resolved by the Illinois Workers' Compensation Commission.
Reporting means giving your employer notice of the accident, which you must do within 45 days (820 ILCS 305/6). Filing the claim is the separate step of submitting an Application for Adjustment of Claim to the Illinois Workers' Compensation Commission if benefits are disputed. Reporting comes first; filing the application follows.
You must give your employer notice of the accident as soon as practicable, but no later than 45 days after it (820 ILCS 305/6). Notice may be oral or written and should state the approximate date and place. Reporting late can jeopardize your right to benefits, so report promptly.
You must file your Application for Adjustment of Claim with the Illinois Workers' Compensation Commission within three years after the date of the accident, where no compensation has been paid, or within two years after the last payment of compensation, whichever is later (820 ILCS 305/6). Missing it bars the claim.
Failing to notify your employer within 45 days can jeopardize your claim. 820 ILCS 305/6 says notice of the accident shall be given to the employer as soon as practicable, but not later than 45 days after the accident. Late reporting gives the insurer grounds to dispute your claim, so report immediately.
Day to day, your employer's insurer decides whether to pay benefits. If you disagree, the Illinois Workers' Compensation Commission resolves the dispute after you file an Application for Adjustment of Claim. An arbitrator first tries the case, and a panel of three commissioners may review that decision.
No. Illinois workers' compensation is a no-fault system, so you do not have to prove your employer did anything wrong to receive benefits. You generally need to show the injury arose out of and in the course of your employment. In exchange, benefits are set by statute rather than a jury.
If your employer's insurer denies, delays, or underpays your claim, you can take it to the Illinois Workers' Compensation Commission by filing an Application for Adjustment of Claim through CompFile. You must do so within the three-year or two-year limitation period (820 ILCS 305/6). Attorney review of your case is available through DocDraft.
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