Illinois business owners who want to operate under a trade name must register an assumed name. Where you file, which form you complete, and whether you must publish a public notice all depend on your business structure. Sole proprietors, general partnerships, and professional corporations file with their county clerk. LLCs, corporations, nonprofits, and limited partnerships file with the Illinois Secretary of State. This guide covers who needs to register, how the process works for each filing path, what every cost looks like, and what ongoing compliance requires.
What is a DBA in Illinois?
A DBA in Illinois, officially called an assumed name, is any name a business or individual uses in commerce that differs from their legal or registered name—"Smith's Hardware" instead of "John Smith," or "Fresh Eats Chicago" instead of "Fresh Eats, LLC."
Registering an assumed name does not create a new legal entity or provide trademark protection. It registers only the right to use a name in commerce.
Illinois assumed name vs. DBA: Are they the same thing?
"DBA," "doing business as," and "assumed name" are interchangeable under Illinois law. The Illinois Assumed Business Name Act (805 ILCS 405) and the Secretary of State's assumed name provisions for LLCs and corporations all refer to the same concept: using a business name in commerce that differs from your legal or registered name.
Why get a DBA in Illinois?
Registering an assumed name offers several strategic advantages for Illinois business owners, impacting everything from how you market your services to how you manage your financial operations.
- Branding under a trade name. A sole proprietor named Jane Doe can operate as "Lakeside Consulting," giving the business a more professional, marketable identity.
- Running multiple business lines under one entity. An LLC providing both web design and photography might register "Pixel Studio" and "Bright Frame Photography" to market each line without forming two separate companies.
- Opening a business bank account. Most banks require an assumed name certificate before opening an account in a trade name.
- Entering contracts under a trade name. A registered DBA lets you sign leases, vendor agreements, and client contracts under your business's public-facing name.
- Protecting your privacy. A DBA lets you promote your business without putting your legal name front and center in every transaction.
- Separating personal identity from business identity. For sole proprietors especially, a DBA creates a clear distinction between personal and business activities, though it does not provide the liability protection of an LLC.
Who needs to register a DBA in Illinois?
Most Illinois businesses and individuals who operate under any name other than their legal or registered name must register an assumed name before doing business under it. Your business structure determines where you file.
- Sole proprietors. Must register with the county clerk in every county where they conduct business if they use any name other than their own full legal name.
- General partnerships. Must register with the county clerk in each county where the partnership conducts business.
- Professional corporations (PCs). Must register with the county clerk if operating under any name other than the corporation's legal registered name.
- LLCs. Must file with the Illinois Secretary of State if operating under any name other than the LLC's registered name.
- Corporations. Must file with the Illinois Secretary of State to use any trade name that differs from the corporation's legal name.
- Nonprofits. Must file with the Illinois Secretary of State to operate under any name other than the organization's registered legal name.
- Limited partnerships (LPs). Must file with the Illinois Secretary of State if conducting business under any name other than the LP's registered name.
One exception: a sole proprietor who operates exclusively under their exact full legal name is generally not required to file.
Where to file in Illinois: Secretary of State vs. county clerk
Your filing destination depends entirely on your business structure. Entities formed with the state, like LLCs, corporations, nonprofits, LPs, file with the Illinois Secretary of State. Sole proprietorships, general partnerships, and professional corporations file with the county clerk in every county where they use the name.
One note for out-of-state businesses: if a foreign LLC's legal name is already in use in Illinois, the state may require it to register under an assumed name before transacting business here.
| Business type | Filing office | Secretary of State form (if applicable) | Renewal cycle | Publication required? |
|---|---|---|---|---|
| LLC | Illinois Secretary of State | Form LLC 1.20 | Every 5 years | No |
| Corporation (for-profit) | Illinois Secretary of State | Application to Adopt, Change, or Cancel an Assumed Corporate Name (Business Corporation Act) | Every 5 years | No |
| Nonprofit corporation | Illinois Secretary of State | Application to Adopt, Change, or Cancel an Assumed Corporate Name (General Not For Profit Corporation Act) | Every 5 years | No |
| Limited partnership (LP) | Illinois Secretary of State | Application to Adopt, Change, or Cancel Assumed Name (IL Uniform LP Act) | Every 5 years | No |
| Sole proprietor | County Clerk (every county where business is conducted) | County-specific assumed name application | No formal renewal required in most counties | Yes — 3 consecutive weeks |
| General partnership | County Clerk (every county where business is conducted) | County-specific assumed name application | No formal renewal required in most counties | Yes — 3 consecutive weeks |
| Professional corporation (PC) | County Clerk (every county where business is conducted) | County-specific assumed name application | No formal renewal required in most counties | Yes — 3 consecutive weeks |
These notes highlight key filing and publication distinctions you should consider based on your registration path.
- State filers: LLCs and corporations can submit applications online through the Secretary of State's filing system, or by mail or in person in Springfield. Your assumed name takes effect on the filing date and remains valid until the first day of your company's anniversary month in the next calendar year evenly divisible by five.
- County filers: If you do business in multiple counties, you must register in every county where you use the name. Confirm renewal rules with your specific county clerk, as practices vary.
- Publication (county filers only): Publication is required at the county level only. State filers have no publication requirement.
Illinois DBA name search and naming rules
Before filing, confirm two things: whether your desired assumed name is available, and whether it meets Illinois's naming rules. A name can be available and still get rejected for violating a naming restriction.
How to search an Illinois DBA name before you file
All business types should first check their preferred assumed name using the Illinois Business Entity Search tool on the Secretary of State's website. The search is free and covers corporations, not-for-profit corporations, limited partnerships, LLCs, and limited liability partnerships.
One important limitation: the state search tool won't find businesses registered at the county level. Sole proprietorships and general partnerships register with the county clerk, not the Secretary of State. Some Illinois counties, including Cook and DuPage, offer online search tools for assumed business names. For counties without one, contact the county clerk directly.
A name search doesn't guarantee approval — only the Secretary of State can determine whether a name is "distinguishable" from existing registrations. It's also worth checking the Illinois Trademark Database and the USPTO Trademark Database, since a pre-existing trademark could create legal exposure even if the state search clears.
Illinois assumed name naming requirements
Before submitting your registration, ensure your proposed name complies with these specific naming standards to prevent application rejection.
- The name must be distinguishable from existing registered names. At the state level, your assumed name must be unique from any corporation, LLC, or entity on record, including reserved names. At the county level, it cannot be identical to one already registered in that county.
- Generic words and common abbreviations don't make a name distinguishable. The state does not consider words like "corporation," "company," "incorporated," "limited," or their abbreviations, along with articles, conjunctions, and contractions, as sufficient to distinguish one name from another.
- Certain terms require additional approval. Words like "bank," "banking," "insurance," "university," and "attorney" are regulated and may require prior approval from a state agency.
- The name cannot imply a government affiliation.
- A foreign entity cannot use an assumed name to misrepresent its geographic origin.
- Two exceptions apply for corporations and LLCs. Registration is not required if the name is a federal or state registered trademark or service mark owned by the entity, or if the assumed name identifies a separate unincorporated division, provided the full legal name is also displayed alongside it.
If you're uncertain whether your name will pass, call the Secretary of State's Springfield Business Service Department at 217-524-8008 or the Chicago Business Service Department at 312-793-3380.
How to file a DBA in Illinois: Step-by-step
The registration process for your assumed name depends on your business structure, with two distinct filing paths available based on whether your entity is state-registered or locally managed.
Steps for LLCs, corporations, nonprofits, and LPs (Secretary of State filers)
- Search for name availability using the Illinois Business Entity Search tool on the Secretary of State's website.
- Confirm your name meets Illinois naming requirements. Availability and compliance are separate questions — review the naming rules above before submitting.
- Complete the correct Secretary of State form for your entity type. LLCs use Form LLC 1.20; corporations use the Application to Adopt, Change, or Cancel an Assumed Corporate Name under the Business Corporation Act; nonprofits use the equivalent form under the General Not For Profit Corporation Act; LPs use the Application to Adopt, Change, or Cancel an Assumed Name under the IL Uniform LP Act. Download the correct form from ilsos.gov.
- Submit your form and pay the filing fee. Domestic and foreign LLCs in good standing may file electronically. Corporations and nonprofits can file online, by mail, or in person. The fee ranges from $30 to $150 depending on the filing year. Cash is not accepted; pay by check, money order, or online payment.
- Receive confirmation from the Secretary of State and keep it on file for bank accounts and business records.
Steps for sole proprietors, general partnerships, and professional corporations (county clerk filers)
County filers have a longer process. Notarization and newspaper publication are both required. Budget extra time and cost accordingly.
- Search for name availability at the county level. Some counties, including Cook, have an online search tool. For counties without one, contact the county clerk directly.
- Obtain and complete your county's assumed name application. There is no single statewide form. Each county clerk maintains its own. The application typically asks for the business name and address, the type of product or service offered, and the names and home addresses of all owners or partners.
- Have the application notarized. All owners and partners must sign in front of a notary public. Some county clerks offer on-site notary service; independent notaries typically charge $5–$15.
- Submit the notarized application and pay the filing fee. Cook County accepts online submissions. Other counties may require mail or in-person filing. Cook County charges $50; other counties range from roughly $10 to $30. Confirm the current fee with your county clerk before submitting.
- Publish your assumed name in a local newspaper. Publication must begin within 15 days of registration and run once a week for three consecutive weeks. The clerk will provide a publication notice form after accepting your application. Contact your county clerk for a list of approved newspapers.
- File the certificate of publication with the county clerk. The newspaper will provide a notarized Certificate of Publication with an original clipping. A photocopy is insufficient. You must submit proof of publication within 50 days of the application. Missing this deadline voids your registration entirely.
Illinois DBA costs: What you'll pay
Registration and compliance fees for your assumed name vary depending on your business structure and the specific filing location.
| Cost item | Amount | Who pays |
|---|---|---|
| Secretary of State filing fee | $30–$150, based on filing year (2026 fee: $120) | LLCs, corporations, nonprofits, LPs |
| Secretary of State renewal fee | $150 (flat, at 5-year renewal) | LLCs, corporations, nonprofits, LPs |
| County clerk filing fee | Varies by county (examples below) | Sole proprietors, general partnerships, PCs |
| Notarization | ~$5–$15 | Sole proprietors, general partnerships, PCs |
| Newspaper publication | Typically $30–$75+ depending on county and publication | Sole proprietors, general partnerships, PCs |
State filing fees shift by year. The fee reflects how many years remain in the current five-year cycle. Filing in 2027 will cost $90.
Renewal fees don't follow the same sliding scale. Renewal costs $150. You can file up to 60 days before expiration. Filing after the deadline adds a $100 late fee.
Publication is a real cost. Budget at least $30–$75 for three consecutive weeks in most Illinois counties; rates in larger metro areas can run higher. Contact your county clerk for approved newspapers, then call the paper directly for current legal notice rates.
Cash is not accepted for state filings. Pay by check, money order, or online payment made payable to the Illinois Secretary of State. County clerks have their own payment policies — DuPage County, for example, accepts cash, check, money order, or credit/debit card (with transaction fees).
Publication requirements for county filers
Filing the application is not the end of the process for county filers. Illinois law under 805 ILCS 405 requires publication of a public notice in a local newspaper before your registration is legally complete.
- What you must publish. The notice must run in a newspaper of general circulation within the county where you filed — not a trade publication, neighborhood newsletter, or online-only outlet. Your county clerk will provide a list of approved publications after accepting your application.
- How long the notice must run. Once each week for three consecutive weeks. The first notice must appear within 15 days of the initial filing. Missing that window can void your registration.
- What you get from the newspaper. After publishing, the newspaper completes the Publisher's Certificate, attaches a copy of the publication, and mails it to you. A photocopy is not acceptable.
- The 50-day deadline. You must file the Publisher's Certificate with the county clerk within 50 days of your original filing date. Miss this deadline and your registration is void, not just late, but legally invalid. You would need to start over.
- After the clerk receives your proof. The clerk will send you a Certificate of Ownership of Business confirming your registration is legally complete. Keep it on file; banks and other institutions may ask for it.
- Operating in multiple counties. Each county where you conduct business requires a separate registration, publication, and proof of publication filed within 50 days.
How long does an Illinois DBA last? Renewal and ongoing compliance
Maintaining your registered assumed name requires ongoing attention to specific renewal and compliance obligations, which vary depending on your entity type and where you originally filed.
Renewing a state-level assumed name (LLCs, corporations, nonprofits, LPs)
Assumed names registered with the Secretary of State must be renewed in all years ending in 0 or 5. The due date falls on the first day of the month in which you originally registered. For example, if you registered on September 13, 2021, renew by September 1, 2025.
Corporations and nonprofits must renew online. LLCs can use the online renewal form for one or two assumed names; renewing more than two requires the paper LLC Assumed Name Renewal form. LPs must use the paper LP Assumed Name Renewal form.
There is a $100 penalty for renewing after the anniversary month begins. Miss the window entirely, and sixty days after the deadline the Secretary of State will cancel the registration — requiring a new adoption application and fee. Corporations can consolidate the renewal with their annual report filing by paying renewal fees alongside annual report fees and franchise taxes.
Renewing a county-level assumed name (sole proprietors, general partnerships, PCs)
County-level assumed names don't require formal renewal in most cases, but practices vary. Contact your county clerk to confirm whether and when renewal is required.
How to amend or cancel an Illinois assumed name
State filers: Use the same Secretary of State form used to adopt the assumed name, marked to indicate a change or cancellation. The cancellation fee follows the same sliding-scale structure as the adoption fee.
County filers: File a Supplemental Assumed Name Certificate with the county clerk indicating the change. Publication is again required when the change involves adding owner names, closing the business, withdrawing owner names when withdrawal involves 25% or more of total ownership, or changing the business address.
County quick-reference: Filing in Illinois's major counties
Illinois has 102 counties, and the assumed name filing process is not uniform across them. Fees, accepted payment methods, online filing availability, and minor procedural steps all vary.
| County | Clerk office | Filing methods | Filing fee | Online name search available? | Notable local notes |
|---|---|---|---|---|---|
| Cook County | Cook County Clerk | Online, in person | $50 | Yes | Online application available through the Cook County Clerk's website. |
| DuPage County | DuPage County Clerk | In person, by mail | $10 | Yes | Cash, check, money order, or credit/debit card accepted (transaction fees apply). Complete the Certificate of Ownership application prior to visiting. |
| McLean County | McLean County Clerk | In person (form may be started online) | $24 | Yes | All owners must appear in person with a driver's license or State ID. In-office notarization available for $1. |
| Will County | Will County Clerk | In person, by mail | $10 | No (monthly registration listings posted online) | Publication must occur within 15 days of initial filing. Certificate of Publication must be submitted within 50 days. |
Publication is required in every county listed. Publication fees are set by individual newspapers; contact the paper directly for current rates.
Online filing availability varies. Cook County allows online registration. DuPage County requires an in-person visit, though you can complete the application in advance. McLean County lets you start the form online, but all owners must appear in person to finalize.
Notarization applies across the board. Each owner must sign with signatures notarized before submitting. Some clerks offer on-site notary services; McLean County charges $1.
Operating in multiple counties means multiple filings. Each county is a separate registration with its own fee, notarization, and three-week publication cycle. There is no consolidated multi-county filing option.
Illinois DBA vs. LLC vs. trademark: What's the difference?
| Feature | DBA (assumed name) | LLC | Federal trademark |
|---|---|---|---|
| Creates a new legal entity | No | Yes | No |
| Limits personal liability | No | Yes | No |
| Protects the name in Illinois | Partially — establishes your right to use the name in commerce, but does not prevent others from registering a similar name | Partially — your LLC's registered name is protected from identical names at the Secretary of State level, but a DBA filed under the LLC does not block similar names | No — federal trademark rights are not geographically limited to Illinois, but registration is separate from any state filing |
| Protects the name nationally | No | No | Yes — exclusive rights across all 50 states |
| Typical cost | Low — $30–$150 for state filers; county fees plus publication typically under $150 total | Higher — Illinois LLC formation fees plus ongoing annual reporting | Higher — USPTO fees start at several hundred dollars per class of goods or services |
| Ongoing compliance | Every 5 years for state filers; county rules vary | Annual reports and fees to the Illinois Secretary of State | Renewal every 10 years; use-in-commerce declarations at the 5-year mark |
| How quickly you can use the name | Immediately upon filing acceptance (state filers); county filers must complete publication first | After Secretary of State approves LLC formation | After USPTO examination and registration, typically 12–18 months |
A DBA is the right tool when you want to operate under a trade name without forming a new entity. If you need personal liability protection, starting an LLC in Illinois is the appropriate step. If protecting your name from competitors nationwide matters, federal trademark registration is the only tool that delivers that exclusivity. Many business owners ultimately need both.
Illinois DBA FAQs
Do I need a separate DBA for each county I operate in?
Sole proprietors and general partnerships must register with the county clerk in every county where they conduct business. State filers, including LLCs, corporations, nonprofits, and LPs, file once with the Secretary of State, and that registration covers the entire state.
What happens if I operate under an unregistered assumed name in Illinois?
Unregistered businesses cannot bring lawsuits in Illinois courts to enforce contracts, meaning you lose the ability to recover debts or uphold agreements. The statute also allows anyone to file a civil action against the business by naming it under its assumed name and designating the owners as "unknown owner or owners," meaning you could be sued without receiving proper notice.
Can an Illinois LLC have more than one DBA?
An Illinois LLC can register as many assumed names as needed, but each requires a separate application and fee. Each assumed name has its own five-year registration cycle. If you're considering how to add a DBA to an LLC, the process involves filing a separate Form LLC 1.20 for each additional assumed name.
Is a DBA the same as a business license in Illinois?
No. An assumed name registration only registers the name you use to conduct business. Depending on your industry and location, you may also need a state business license, local municipal license, or professional license. Separate requirements that exist regardless of whether you have a registered DBA.
Can a sole proprietor use their own full legal name without filing a DBA?
A sole proprietor who operates exclusively under their exact full legal name is generally not required to file an assumed name registration in Illinois. The filing requirement is triggered only when you use any name other than your own legal name in commerce.
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