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How Do I Get Private Investigator's License in Illinois?

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Obtaining a private investigator’s license in Illinois is a multistep process that is designed to validate experience as an investigative professional. A 90-minute exam consisting of 75 questions is required to obtain an Illinois license. Federal and state law, licensing and practice requirements, and detective practices are the areas that are covered on the exam. Prior to the exam, the candidate must have verifiable education or work experience in a related field. For instance, many private investigators are former law enforcement officers or hold a criminal justice degree.

Obtain a private investigator’s application packet from the Illinois Department of Professional Regulations (IDPR). The packet is available online at the IDPR.com website as well as in person at IDPR offices.

Complete and submit the packet per the included instructions. Notification of acceptance or denial of candidacy will be sent after a review. Once candidacy is accepted, move to the next step.

Select a written test date from the list of available dates at Continentialtesting.net’s website (see Resources). The last day to register is typically six or seven weeks prior to the exam date. The exam deadlines are listed with the exam dates on the website.

Complete the online application for private investigator licensure at Continentialtesting.net and pay the required exam fee. Confirmation of the test date, time and location will be sent at least 10 days prior to the exam date.

Study for the exam. Review the licensure requirements and obtain the study materials outlined in the packet. According to the IDPR, the following are recommended books for exam study: "Illinois Criminal Law and Procedures Handbook," "Private Detective," "Private Alarm," "Private Security and Locksmith Act and Rules," "Illinois Handbook of Government" and "Criminal Investigation." It is also advisable to take the practice test questions included with the exam requirements.

Take the licensure exam on the scheduled date and wait for the results. A score of 70 percent or better is required to pass. Upon passing the exam, the candidate will receive a “Pass” notice and an application for licensure. If the exam is not passed, the candidate will receive a failure notice, including a retesting application.

Complete the application for licensure per the instructions provided and wait for issuance of the license.


Many candidates who fail the licensure exam on the first try go on to pass it after subsequent testing. Therefore, candidates are encouraged to retest if they don’t pass the first time around.

Candidates with physical disabilities may complete a form available at the IDPR’s website that will allow for reasonable accommodations while taking the test. These accommodations include extra testing time, extra breaks and a helper to read or record the test questions and answers.


If a private investigator’s licensure exam date is missed, there are no refunds or “makeup” exams.

About the Author

Cheri Pearson is a professional writer/marketing professional, with experience in copywriting, technical and marketing communications, articles, and ghostwriting for private and corporate clients since 1994. She has a bachelor's degree in business administration from the University of Illinois, and a background in medical device marketing/product management in the renal industry.

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