In Illinois, a medical malpractice lawsuit against a licensed physician, dentist, registered nurse or hospital generally cannot be brought more than two years after the patient knew, or through reasonable diligence should have known, of the injury or death, and in no event more than four years after the act or omission that caused it (735 ILCS 5/13-212). Longer periods can apply to minors and to people under a legal disability, and fraudulent concealment has its own rule. Call Stavros Law Offices at (847) 520-4810 for a free consultation and bring your dates.

General information, not legal advice. Last reviewed: October 2026.

The Basic Rule: Two Years and Four Years

Medical malpractice claims are covered by their own statute, 735 ILCS 5/13-212, rather than the general two-year personal injury rule. The statute covers actions for damages for injury or death against a physician, dentist, registered nurse or hospital duly licensed in Illinois that arise out of patient care, whether the claim is based on negligence, breach of contract or otherwise. It sets two separate limits:

• The two-year limit. The action cannot be brought more than two years after the date the claimant knew, or through the use of reasonable diligence should have known, or received written notice of the existence of the injury or death, whichever of those dates occurs first.
• The four-year outer limit. Even if the injury was not discovered, the action cannot be brought more than four years after the date of the act or omission or occurrence alleged to have caused the injury or death. Lawyers call this a statute of repose.

Both limits matter. A claim can be late under the two-year rule even though the four-year limit has not yet passed, and the four-year limit can end a claim that was discovered late.

When Does the Two-Year Clock Start?

For malpractice claims, the clock does not necessarily start on the date of the treatment. The statute looks to the earliest of three things: when the claimant actually knew of the injury or death, when the claimant should have known through reasonable diligence, or when the claimant received written notice of it. Written notice can therefore matter even if the patient did not understand its significance at the time, so keep any letters or reports you received.

Courts decide these questions case by case, based on the facts, including when the patient first learned of the injury (as opposed to the underlying illness) and when it was reasonably apparent that it might be connected to the care given.

Because the answers are fact-specific, the safest approach is to treat the earliest possible date as the starting point until an attorney tells you otherwise. Do not rely on the discovery language alone as your plan. The four-year outer limit still applies.

A Simple Illustration

This example is only an illustration of how the two periods can work together, not a prediction about any case. Suppose a scan is misread in March 2022, and the patient first learns of the missed condition in June 2024. Two years from June 2024 would be June 2026. But four years from the March 2022 misreading is March 2026, which comes first, so under the statute's wording the outer limit would control. Real cases involve more facts, such as ongoing treatment and what the records said, and an attorney needs to review them.

Children and Minors

If the patient was under 18 when the claim accrued, 735 ILCS 5/13-212(b) provides that the action may not be brought more than eight years after the act or omission, and in no event after the person's 22nd birthday. In plain terms:

• A child who was a toddler when the act occurred would measure the eight years from the act itself, so the end date would be well before the 22nd birthday.
• A teenager who was 16 when the act occurred would reach the 22nd birthday before eight years pass, so the 22nd birthday would be the outer limit.

These are illustrations of how the statute's numbers fit together, and the statute's text should be applied with an attorney to the actual facts. Birth injury claims often involve this rule. See our page on birth injury claims in Illinois. Do not wait for a child to grow up to explore a claim, since evidence and records are easier to gather sooner.

Patients Under a Legal Disability

735 ILCS 5/13-212(c) says that if the person entitled to bring the action was, when the claim accrued, under a legal disability other than being under 18, the period of limitations does not begin to run until the disability is removed. Subsection (d) addresses a person who becomes disabled after the claim accrued but before the period runs out: the period is stayed until the disability is removed, and the subsection does not invalidate the statute of repose in that section. Whether a person qualifies as legally disabled is a legal question that depends on the facts.

Fraudulent Concealment

Under 735 ILCS 5/13-215, if a person liable fraudulently conceals the cause of action from the knowledge of the person entitled to bring it, the action may be commenced at any time within five years after the person discovers that he or she has the cause of action, and not afterwards. Section 13-212 itself says it applies “except as provided in” Section 13-215.

This is not a general extension for every case where something was left out of a chart. Concealment must be shown, and courts look closely at what was actually hidden and by whom. It is a narrow exception and should not be treated as a fallback.

If the Patient Died

Section 13-212 refers to an action for “injury or death.” A wrongful death action is also governed by the Wrongful Death Act, which has its own rules about who may bring the claim (the personal representative) and its own timing provisions. Families should not assume which period applies. See our page on wrongful death claims in Illinois, and speak with an attorney quickly.

Public Hospitals and Government Bodies

If the provider is a local public entity or its employee, a separate statute, 745 ILCS 10/8-101, applies, with its own time periods and a different rule for claims arising out of patient care. Tell us at the start if the hospital or clinic was run by a public body.

How the Deadline Connects to the 2-622 Report

A malpractice complaint must be accompanied by an affidavit and a written report from a qualified health professional (735 ILCS 5/2-622). That takes time to arrange. The statute has narrow provisions for situations in which the consultation could not be obtained before a limitations period expired, or where requested records were not produced within 60 days, but these provisions are limited, and a lawyer should not plan around them. Records requests alone can take up to 30 to 60 days under 735 ILCS 5/8-2001, so starting early leaves room for records, review and filing. For the full sequence, see how a medical malpractice lawsuit works in Illinois.

What to Bring to a Consultation

• The dates of each procedure, visit or hospital stay involved.
• The date you first learned something was wrong, and how you learned it.
• Names of providers and facilities, plus any discharge papers, test results or letters you received.
• For a child, the child's date of birth.

Return to our main page on medical malpractice in Illinois, or read our general guide to the Illinois personal injury statute of limitations.

Frequently Asked Questions

How long do I have to file a medical malpractice lawsuit in Illinois?

Generally, an action against a licensed physician, dentist, registered nurse or hospital cannot be brought more than two years after the claimant knew or should have known of the injury or death, and in no event more than four years after the act or omission (735 ILCS 5/13-212). Exceptions exist for minors, legal disability and fraudulent concealment.

What is the difference between the two-year and four-year limits?

The two-year limit runs from when the claimant knew, should have known, or received written notice of the injury or death, whichever is first. The four-year limit is an outer limit that runs from the act or omission itself, even if the injury was found later.

What is the deadline if the patient was a child?

If the patient was under 18 when the claim accrued, 735 ILCS 5/13-212(b) provides that the action may not be brought more than eight years after the act or omission, and never after the person's 22nd birthday. Have an attorney review the specific dates.

What if the provider hid the mistake?

Under 735 ILCS 5/13-215, if a liable person fraudulently conceals the cause of action, the action may be commenced within five years after the person discovers it. Concealment must be proven, and it is a narrow exception that should not be relied on.

Does the deadline change if the patient died?

Section 13-212 refers to injury or death, but a wrongful death claim also has its own statute, including rules about who may bring the claim. Do not assume which period applies. Speak with an attorney promptly.

Talk to Our Team

Stavros Law Offices is one team handling criminal defense and DUI, personal injury and civil litigation. Call (847) 520-4810 or request a free consultation online. Our bilingual staff can assist. Se habla español.

Stavros Law Offices
433 N. Milwaukee Ave, Wheeling, IL 60090
(847) 520-4810
Monday–Friday 9–5; closed Saturday
Serving clients in Cook, Lake, McHenry, Kane and DuPage Counties.

General information, not legal advice; no attorney-client relationship until engaged; past results do not guarantee a similar outcome. Laws and deadlines change and every case is different. Last reviewed: October 2026.