How to File an Illinois DBA

How to Use this Guide

To file a DBA in Illinois, use the step-by-step guide below or hire a professional service to do it for you:

  • LegalZoom ($99 + state fee) if you want to use the most popular DBA filing service with free extra features.
  • CorpNet ($108 + state fee) if you want to use the DBA filing service with the best customer support.
Amy M. Toepper, Esq.
This Guide is Attorney Approved

Amy Toepper is a licensed Illinois attorney & founder of Legal In A Box.

For a legal advisor on your side, set up a free consultation.

Step 1) Obtain A Copy Of The Assumed Business Name Application


Once you’ve selected the business name you want to file under, you will need to ensure the name is available and there are no trademark issues:

Follow these steps:

1.   Check with the local county clerk’s office, which is also where you’ll need to get your DBA registration form.

2.   Conduct a Business Search through the IL Secretary of State’s website.

3.   Conduct a TESS System search through the U.S. Patent & Trademark Office.

Step 2) Properly Fill Out The Application Form


You will need to obtain a copy of the ‘doing business as’ application form from your local Illinois county clerk’s office. If you don’t have legal counsel or a DBA filing service assisting you, take your time completing this form and make sure each entry is correct.

Follow this step:

  • Read all instructions and answer each question to the best of your ability. Specific information about your Illinois DBA business needs to be provided.

Step 3) Mail In The Application Form


The final step is to mail the finished Illinois DBA application form after being notarized along with your application fee.

Follow these steps:

1.    Sign the application and ensure you get it notarized!

2.    Mail the signed application to the mailing address provided by the county clerk on the form itself, along with the application fee.

3.    Once you have mailed the form, you will need to publish the assumed name in the local newspaper for 3 consecutive weeks, something the clerk can assist with as well!

Need Help Filing a DBA?

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Note that this Illinois DBA registration guide is not legal advice. If you’re looking for expert advice on filing an Illinois DBA or starting a business in general, please schedule an appointment with an accredited attorney. We highly recommend Amy Toepper.