Business Registration

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

  • electronically register through MyTax Illinois (approximately one to two days to process);
  • complete and mail Form REG-1, Illinois Business Registration Application, to us at the address on the form (Form REG-1 is available on our web site as a fill-in and savable form. Registration forms are also available by calling us at 1 800 356-6302.); or
  • visit one of our offices.

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

  • Schedule REG-1-A, Liquor Information,
  • Schedule REG-1-C, Cigarette and Tobacco Products Information,
  • Schedule REG-1-D, Electricity Tax Self-Assessing Purchaser,
  • Schedule REG-1-G, Gas Use Tax Self-Assessing Purchaser,
  • Schedule REG-1-L, Illinois Business Site Location Information,
  • Schedule REG-1-MR, Illinois Cigarette Manufacturer's Representative,
  • Schedule REG-1-O, Owner and Officer Information,
  • Schedule REG-1-R, Responsible Party Information, and
  • Schedule REG-1-T, Telecommunications Tax Location Information.

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,

  • your returns and payments may not be processed correctly;
  • we may send you a tax bill or notice; and
  • you may not receive the forms or needed information about tax law changes.

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 "Questions, Comments, or Requests" link at the bottom of every Question & Answer page.