Illinois EIN Lookup
Last updated November 5, 2026 · Written by the EIN Registration filing team
Look up a Illinois company
Illinois only allows its search on its own site, so this opens in a new tab. It finds the company, not usually its EIN.
No EIN yet for your Illinois business?
We file the SS-4 for you. EIN typically emailed in 2 to 4 business days (about 11 by fax).
Where to look in Illinois
- Illinois Secretary of State business entity search. Search by business name, keyword, registered agent, officer or file number. Use it to confirm the company's exact name and status.
- MyTax Illinois: Verify a Registered Business. Under the Searches panel, with no login. Takes an Illinois Account ID, FEIN or license number and shows whether the business is registered with the Department of Revenue. It checks a number you already have.
Illinois numbers that get mistaken for an EIN
None of these is the nine-digit federal number unless the table says so. A bank, payroll company or client asking for your EIN wants the one the IRS issued.
| Used for | Issued by | The number |
|---|---|---|
| Company formation | Illinois Secretary of State, Department of Business Services | file number |
| State income tax withholding | Illinois Department of Revenue | Your federal EIN (FEIN with a three-digit sequence number) |
| Unemployment insurance | Illinois Department of Employment Security | Account number issued at registration |
| Sales tax | Illinois Department of Revenue | Sales tax Certificate of Registration |
Finding your own Illinois company’s EIN
Start with the CP 575 letter the IRS sent when the number was issued, then a past federal return, your bank’s account paperwork and your payroll provider. If none of those has it, the responsible party can call the IRS and ask for a 147C letter. Do not apply again to replace a lost number: a second application creates a second EIN for the same company.
Finding another Illinois company’s EIN
If you pay them, ask for a Form W-9: it is the normal way to get the number, and you need it for a 1099 anyway. Nonprofits are in the IRS Tax Exempt Organization Search, and public companies print theirs on SEC filings. For a private Illinois company with no reason to give it to you, there is no free public source that is complete. To check a number you were given, see how to verify an EIN.
Illinois EIN lookup questions
Does Illinois have an EIN lookup?
The EIN is federal, so the IRS issues it and Illinois does not. Illinois Secretary of State business entity search finds a company by business name, keyword, registered agent, officer or file number. Do not count on it for the federal number. The reliable sources are the company itself, on a Form W-9, or your own IRS paperwork if the company is yours.
Is my Illinois file number my EIN?
No. The file number comes from the Illinois Secretary of State, Department of Business Services and identifies your company in state records. The EIN comes from the IRS, and a bank or payroll company asking for one will not accept the state number.
I formed my Illinois company but never got an EIN. What now?
Forming the company does not create an EIN. You apply separately with the IRS on Form SS-4, or a service like ours prepares and files it for you. If you might already have one, check first: applying again gives the same company a second number.
Get Your EIN the Easy Way
Answer a few questions in about 5 minutes. Our specialists prepare your IRS Form SS-4, file it, personally handle any rejection or name conflict along the way, and get your EIN to you, typically within 2 to 4 business days, or about 11 when the IRS requires the application by fax. One flat $197 service fee. No upsells, no subscriptions.
- ✓ Prepared and filed by specialists
- ✓ Error 101 and rejection handling included
- ✓ Data encrypted (AES-256)
- ✓ Order tracking and email updates
Related guides
Sources
You can also apply for an EIN directly with the IRS at irs.gov at no cost.