Illinois expert witness: experts for Illinois state and federal courts.
Expert Witness Networks places board-certified physicians, licensed specialists and technical experts on Illinois cases for record review, written opinions, deposition and trial testimony. Serving Chicago, Aurora, Naperville, Joliet and Rockford and every county statewide.
How Illinois courts treat expert testimony
The rules every expert must meet in Illinois, medical or not.
Frye
Illinois uses the Frye general-acceptance test, codified in Ill. R. Evid. 702, which applies only to new or novel scientific methods (Donaldson v. Central Illinois Public Service Co., 199 Ill.2d 63 (2002); In re Commitment of Simons, 213 Ill.2d 523 (2004)). Other expert testimony is judged under ordinary Rule 702 qualification and helpfulness standards.
Trial courts are the circuit courts organized into judicial circuits, with the Circuit Court of Cook County the largest. Appeals go to the Illinois Appellate Court (five districts), and the highest court is the Illinois Supreme Court.
- U.S. District Court, Northern District of Illinois
- U.S. District Court, Central District of Illinois
- U.S. District Court, Southern District of Illinois
Illinois medical expert requirements
What a medical expert must satisfy before testifying in a Illinois malpractice case.
Who qualifies as a medical expert
735 ILCS 5/8-2501 has no percentage-of-time test and no board-certification requirement. Courts weigh the relationship of the expert’s specialty to the medical problem, whether the expert spends a substantial portion of time in practice, teaching or university research, whether the expert is licensed in the same profession as the defendant, and, for non-specialist defendants, familiarity with the Illinois standard of care. Same-profession licensure is the firm line (Sullivan v. Edward Hospital (2004)).
Certificate, affidavit or presuit requirement
Under 735 ILCS 5/2-622, the complaint must attach an attorney affidavit plus a written report from a reviewing health professional for each defendant. The reviewer must have practiced or taught in the same area of medicine within the last 6 years and, against a physician, hold the same profession and class of license. A 90-day extension is available when limitations is about to expire.
Out-of-state experts
No Illinois license, registration or fee is required to testify. The requirement is licensure in the same profession, not licensure in Illinois.
Statute of limitations
Two years from when the claimant knew or should have known of the injury, with a 4-year repose period from the act or omission. Minors have 8 years from the act, but never past their 22nd birthday (735 ILCS 5/13-212).
Damage caps
Illinois has no damage cap. Lebron v. Gottlieb Memorial Hospital (Ill. 2010) struck down the 2005 noneconomic caps, and no cap has been enacted since.
Case & Record Review
Thorough review of records, imaging, reports and evidence.
Written Opinions
Clear, defensible expert reports and affidavits.
Deposition Testimony
Prepared, credible testimony under examination.
Trial Testimony
Plain-language explanation for judge and jury.
Defense and prosecution experts in Illinois
Due process entitles indigent defendants, including in non-capital cases, to a court-funded expert when the expert’s testimony is crucial to a proper defense (People v. Lawson, 163 Ill.2d 187 (1994), applying Ake v. Oklahoma). 725 ILCS 5/113-3 also provides for payment of investigative and expert fees for indigent defendants in certain cases.
We place experts in homicide, abusive head trauma (shaken baby), child abuse and non-accidental trauma, competency and criminal responsibility, and vehicular cases.
Experts we place on Illinois cases
A sample of our roster. Beyond medicine we also place engineers, architects, geologists, meteorologists, questioned-document examiners, DNA specialists and attorney experts.
Questions attorneys ask about Illinois experts
Is Illinois a Frye or Daubert state?
Frye. Ill. R. Evid. 702 codifies the general-acceptance test, but it applies only to new or novel scientific methods (Donaldson, 2002; Simons, 2004).
Who can write the 2-622 health professional report in Illinois?
A health professional who has practiced or taught in the same area of medicine within the last 6 years and is knowledgeable about the issues. Against a physician, the reviewer must hold the same profession and class of license (735 ILCS 5/2-622).
Does Illinois cap medical malpractice damages?
No. Lebron v. Gottlieb Memorial Hospital (2010) struck down the caps, and none has been re-enacted.
How long do you have to sue for medical malpractice in Illinois?
Two years from discovery, but never more than four years after the act or omission. Minors’ claims must be filed within 8 years and before age 22 (735 ILCS 5/13-212).
Can Expert Witness Networks provide an expert for a Illinois case?
Yes. Our experts travel and testify in Illinois state and federal courts for plaintiff and defense counsel, prosecutors, pro se parties and private individuals. You receive the expert’s CV and fee schedule before anything proceeds.
Sources
This page summarizes Illinois law for general information as of 2026 and is not legal advice. Statutes and case law change; confirm current requirements for your matter.
Tell us what your case requires.
Call or write with the specialty, the issues in dispute and your deadline. We will find the right fit.
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