How to Register a Business Name in Illinois

by Jackie Lohrey; Updated September 26, 2017

The Illinois Assumed Business Name Act requires sole proprietorships, general partnerships and professional service corporations to register their business name with their county clerk if it does not explicitly identify the owner or owners. For example, a name such as “Ted’s Tree Service” falls under the Act, while “Landscape Designs by Ted Smith” does not.

In addition to submitting a name registration application online, by mail or in person, you’ll also need to inform the public via your local newspaper and provide proof that you did. It can take 45 to 50 days to get an Assumed Name Certificate, depending on how you apply and on how soon you submit proof of publication.


  • Registering your business name is not the same as registering your business. All businesses must register with the Illinois Revenue Department regardless of the business structure. If your business structure is a corporation, a limited liability company, a limited partnership or a non-profit organization, register your business with the Illinois Secretary of State as well.

Step 1

Contact the clerk’s office for your county, or visit its website if the office maintains a county website. Ask for or download the Assumed Name Application, or create a user profile and complete the application online.

Step 2

Provide the required information. For both paper and online applications, this includes the business name and address, a brief description about its purpose, and names and contact information for all owners.

If you’re applying online, submit the form and the application fee, and then print the application.

Step 3

All the owners must sign the application, and a licensed Notary Public must notarize it, before it is mailed to the clerk’s office or delivered in person during regular business hours. Include the application fee if you haven’t already paid it online.

Step 4

Publish the legal notice once a week for three consecutive weeks in your local newspaper. The clerk’s office will provide a copy of the required notice after you submit the application and pay the fee.

You must publish the notice within 15 calendar days from the date the clerk’s office receives your application.

Step 5

Submit proof of publication -- a notarized Certificate of Publication along with an original clipping or photocopy of the published legal notice -- within 50 days from the application date. The local newspaper will provide you with the notarized certificate.

The clerk’s office then will issue an Assumed Business Name Certificate and register the business name after receiving the required proof. Same day service is usually available if you deliver proof of publication in person.

About the Author

Based in Green Bay, Wisc., Jackie Lohrey has been writing professionally since 2009. In addition to writing web content and training manuals for small business clients and nonprofit organizations, including ERA Realtors and the Bay Area Humane Society, Lohrey also works as a finance data analyst for a global business outsourcing company.