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Business Registration

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 be issued a Certificate of Registration or License and taxpayer ID (i.e., your “tax” number).

IDOR will no longer be printing and mailing certificates for certain tax types including:   

  • Retailers' Occupation Tax Act (35 ILCS 120/)       
  • Use Tax Act (35 ILCS 105/)     
  • Service Use Tax Act (35 ILCS 110/)
  • Service Occupation Tax Act (35 ILCS 115/)
  • Hotel Operators' Occupation Tax Act (35 ILCS 145/)
  • Automobile Renting Occupation and Use Tax Act (35 ILCS 155)
  • Rental Purchase Agreement Occupation and Use Tax Act (35 ILCS 180)
  • Parking Excise Tax Act (35 ILCS 525/)
  • Medical Cannabis Cultivation Privilege Tax (410 ILCS 130/)
  • Dry-Cleaning Solvents Tax (415 ILCS 135/)
  • Cannabis Cultivation Privilege Tax (410 ILCS 705/60)
  • Cannabis Purchaser Excise Tax Act (410 ILCS 705/65)

These certificates will be issued electronically. MyTax Illinois is the primary method you should use to obtain and print a copy of your Certificate of Registration or License. From your MyTax Account, the Certificate of Registration or License is located by selecting "View more account options" and then "View Account Letters" in the "Letters and Messages" panel. 

If you are unable to print a copy of your Certificate of Registration or License, you can also contact our Central Registration Division to request a paper copy be mailed to you. Please include your Illinois account ID or license number and business name in your request.

Register with us, using one of the above methods, before you make any purchases, sales, or hire an employee. 

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 or, 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.

PO BOX 19030

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