Skip to main content
Taxpayer Answer Center

Quick Links

Information For

About IDOR


How do I Register my Business?

person on a computer

You must register with the Illinois Department of Revenue if you conduct business in Illinois, or with Illinois customers. This includes sole proprietors (individual or husband/wife/civil union), exempt organizations, or government agencies withholding for Illinois employees.

To register your business you must

In addition, you may have to complete corresponding schedules, such as

Please allow 6 to 8 weeks for processing if you complete and mail Form REG-1 to us.

If applicable, you will receive your certificate of registration and taxpayer ID (i.e., your “tax” number) in the mail.

Register with us, using one of the above methods, before you make any purchases, sales, or when you hire an employee. You must display your Certificate of Registration in a prominent location in the place of business to which it applies.

If your business is already registered and your information changes (e.g., address change, ownership change, additional tax responsibilities, new location), update your registration information

If you do not,

Contact us, at 217-785-3707, if you do not receive forms to file for your tax responsibilities.

If you prefer, you may also contact our Central Registration Division by mail.

Central Registration Division
Illinois Department of Revenue
PO Box 19030
Springfield IL 62794-9030

Additionally, find answers to your frequently asked tax questions and more with our Taxpayer Answer Center. If you are unable to find your answer after searching the Taxpayer Answer Center, you may contact us via email by using the "Submit a question" form at the bottom of the page.

Other Helpful Resources