Illinois DBA Filing (Assumed Name): Forms & Steps (2026)

Q: What is a DBA called in Illinois?

In Illinois a DBA is called an assumed name. Sole proprietors and general partnerships register an assumed business name with the county clerk; LLCs and corporations register an assumed name with the Illinois Secretary of State.

Q: How do I file a DBA in Illinois as a sole proprietor?

File an assumed business name certificate with the county clerk in the county where your business is located, then publish notice in a local newspaper once a week for three consecutive weeks and file proof of publication with the county clerk, as required by the Assumed Business Name Act.

Q: How does an Illinois LLC file a DBA?

An LLC files an Application to Adopt an Assumed Name (Form LLC-1.20) with the Illinois Secretary of State. Corporations file the corporate assumed name form. The assumed name must be renewed on Illinois's five-year renewal cycle.

Q: Do I need a DBA in Illinois?

You need one if you operate under a name different from your legal name. A sole proprietor using any name other than their own personal name needs an assumed business name, and an LLC or corporation using a name other than its exact registered name needs an assumed name.

Q: Does a DBA protect my business name in Illinois?

No. An assumed name lets you operate under that name but does not give exclusive rights to it. Only a trademark registration provides enforceable brand protection, and forming an LLC reserves the exact entity name in the state.

Fact-checked by the LegalGlass editorial team against primary sources · Published Aug 6, 2026 · Last updated Aug 6, 2026

In Illinois a DBA is an "assumed name." Sole proprietors and general partnerships register it with the county clerk under the Assumed Business Name Act and must publish newspaper notice; LLCs and corporations file an assumed-name application - Form LLC-1.20 for LLCs - with the Illinois Secretary of State. Which office you use depends entirely on your business structure.

Quick Answer

Illinois term: Assumed name (DBA / "doing business as")
Sole prop / partnership: County clerk, Assumed Business Name Act (805 ILCS 405)
LLC: Form LLC-1.20 with the Illinois Secretary of State
Publication: County track requires newspaper notice, 3 consecutive weeks
Renewal: SOS assumed names renew on a 5-year cycle (years ending in 0 or 5)
Protection: None - a DBA is not a trademark and grants no exclusive rights

What a DBA (Assumed Name) Is in Illinois

A DBA - "doing business as" - lets you operate under a name that is not your own legal name. In Illinois the legal term is assumed name. It does not create a new legal entity; it simply registers a public-facing name for an existing person or business. A freelancer named Maria Lopez who brands herself "Prairie State Design" needs an assumed name; an LLC legally named "Lopez Ventures LLC" that wants to run a storefront called "Prairie State Design" also needs one.

Where you register depends on your structure, and Illinois splits DBAs into two tracks: a county track for sole proprietors and general partnerships, and a state track for LLCs and corporations. Using the wrong office is the most common mistake. For the national concept, see what is a DBA.

Two Tracks: County vs. Secretary of State

Your structure	Where to file	Governing law / form
Sole proprietor	County clerk (business's county)	Assumed Business Name Act, 805 ILCS 405
General partnership	County clerk (business's county)	Assumed Business Name Act, 805 ILCS 405
LLC	Illinois Secretary of State	Form LLC-1.20 (805 ILCS 180/1-20)
Corporation	Illinois Secretary of State	Corporate assumed name application (BCA)

The reason for two tracks is that LLCs and corporations are already registered statewide with the Secretary of State, so their assumed names attach to that state record. Sole proprietors and general partnerships are not registered with the state at all, so their assumed names are recorded locally at the county level.

Sole Proprietors and Partnerships: County Clerk Filing

If you run a sole proprietorship or general partnership and use any name other than your own full legal name, the Assumed Business Name Act (805 ILCS 405) requires you to file an assumed business name certificate with the county clerk of the county where the business is located. The steps are:

Check name availability with the county clerk; some counties also let you search online.
Complete the assumed business name certificate, listing the assumed name and the true name and address of each owner.
File it with the county clerk and pay the county's filing fee. Fees are set by each county, not the state, so amounts vary by county - confirm with your county clerk.
Publish and file proof as described below.

Because the county clerk sets the fee and the exact certificate format, the process differs slightly from county to county, but the Assumed Business Name Act requirements - including publication - apply statewide.

The Newspaper Publication Requirement

The county track has a step the state track does not: publication. Under the Assumed Business Name Act, after filing the certificate you must publish notice of your assumed name in a newspaper of general circulation in the county once a week for three consecutive weeks. You then file proof of publication with the county clerk, and the Act sets a short window (generally within 15 days after filing) to begin publication. If you skip publication, the registration is not complete and the Act provides penalties.

Newspaper publication costs are separate from the county filing fee and are paid to the newspaper. Many local papers handle assumed-name notices routinely and will send the required proof (a certificate of publication) directly to you or the clerk. Keep that proof with your business records. If your county has no qualifying newspaper of general circulation, the Act allows publication in a newspaper in an adjoining county, so ask the county clerk which publications qualify before you place the notice. Missing or defective publication is a frequent reason a bank rejects a DBA account application, so complete all three weeks and file the proof before you try to open an account in the trade name.

LLCs and Corporations: Assumed Name with the Secretary of State

An LLC that wants to operate under a name different from its exact registered name files an Application to Adopt an Assumed Name (Form LLC-1.20) with the Illinois Secretary of State under Section 1-20 of the LLC Act (805 ILCS 180/1-20). A corporation files the corresponding corporate assumed name application under the Business Corporation Act. There is no newspaper publication requirement on the state track - that requirement applies only to the county sole-proprietor and partnership track.

The assumed name must itself satisfy Illinois naming rules: it must be distinguishable from existing names and cannot imply a different entity type. Run an Illinois business entity search first. To retire an assumed name, an LLC files a cancellation; to change it, cancel the old one and adopt a new one. For the LLC itself, see Illinois Articles of Organization and how to form an LLC in Illinois.

Assumed Name Fees and Renewal

On the state track, the LLC assumed-name fee is set in the LLC Act fee schedule (805 ILCS 180/50-10) and is prorated over Illinois's five-year renewal cycle: the amount depends on how many years remain until the next renewal year (years ending in 0 or 5). Because of that proration, confirm the exact current amount on the Secretary of State's assumed name page before you file. The assumed name then must be renewed each five-year cycle, or it lapses.

On the county track, the county clerk sets the filing fee, and assumed business name certificates are generally valid for a set term before renewal (commonly five years), which again varies by county. Budget separately for newspaper publication. See Illinois LLC cost for how a DBA compares with forming an LLC.

When You Need a DBA - and When You Don't

You generally need an Illinois assumed name when:

You are a sole proprietor using anything other than your exact personal name.
Your LLC or corporation markets under a brand different from its registered legal name.
A bank asks for a DBA registration before opening an account in the trade name.

You do not need a DBA to operate an LLC under its own registered name, and a DBA is not a substitute for forming an LLC - it gives you a name, not liability protection. If your main goal is to separate personal and business liability, compare sole proprietorship vs LLC before choosing a DBA.

DBA vs. LLC vs. Trademark

These three are often confused. An assumed name registers a name for public use but gives no exclusive rights. Forming an LLC creates a separate legal entity and reserves the exact entity name in Illinois, but does not by itself protect a brand nationally. A trademark - registered with the USPTO or the state - is what gives enforceable, exclusive rights to a brand name or logo. Many businesses use all three: an LLC for liability, an assumed name for a storefront brand, and a trademark to protect the brand. See how to trademark a business name and do I need to trademark my business name.

After You File: EIN, Bank Account, and Taxes

Registering an assumed name does not change your tax situation, but a few follow-ups matter. A sole proprietor can use their SSN or get a free EIN; an LLC uses its own EIN. Banks typically ask for the stamped assumed-name filing (and, for the county track, proof of publication) before opening an account in the DBA name. If you sell taxable goods or services, register with the Illinois Department of Revenue on Form REG-1 and collect sales tax; see Illinois LLC tax filing and business licensing in Illinois.

Frequently Asked Questions

What is a DBA called in Illinois?

An assumed name. Sole proprietors and general partnerships register with the county clerk; LLCs and corporations register with the Illinois Secretary of State.

How do I file a DBA in Illinois as a sole proprietor?

File an assumed business name certificate with your county clerk, then publish notice in a local newspaper once a week for three consecutive weeks and file proof of publication.

How does an Illinois LLC file a DBA?

File Form LLC-1.20, Application to Adopt an Assumed Name, with the Illinois Secretary of State. There is no publication requirement on the state track. See Illinois Articles of Organization.

Do I need a DBA in Illinois?

Yes, if you operate under a name different from your legal name. An LLC operating under its own registered name does not need one.

Does a DBA protect my business name in Illinois?

No. It lets you use the name but grants no exclusive rights. Only a trademark provides enforceable brand protection.

Sources

Illinois Assumed Business Name Act - 805 ILCS 405/1, Certificate; publication requirement (county filing; newspaper notice, 3 consecutive weeks).
Illinois Assumed Business Name Act - 805 ILCS 405/4, Penalty for failure to file.
Illinois Assumed Business Name Act - 805 ILCS 405 (full Act).
Illinois LLC Act - 805 ILCS 180/1-20, Assumed name (LLC assumed-name adoption and renewal).
Illinois LLC Act - 805 ILCS 180/50-10, Fees (assumed name proration; renewal cycle).
Illinois LLC Act - 805 ILCS 180/1-10, Name (distinguishability).
Illinois Secretary of State - Limited Liability Companies (assumed name forms).
Illinois Secretary of State - Department of Business Services home.
Illinois Department of Revenue - Business Registration (Form REG-1).
IRS - Doing Business As (DBA) and business names.
IRS - Get an Employer Identification Number (free EIN).
IRS - Sole Proprietorships.
Cornell Law LII - Trade name (legal definition).

LegalGlass provides general information for educational purposes and is not a law firm or a substitute for advice from a licensed attorney or tax professional. Fees, county procedures, and renewal cycles change; verify current requirements with your county clerk and the Illinois Secretary of State before acting.