EIN Number Illinois: What MyTax Illinois and REG-1 Need
Last updated November 1, 2026 · Written by the EIN Registration filing team
Get the EIN for your Illinois business
We file the SS-4 for you. EIN typically emailed in 2 to 4 business days (about 11 by fax).
After your EIN in Illinois
| Account | Agency | Number you get | Register |
|---|---|---|---|
| State income tax withholding | Illinois Department of Revenue | Your federal EIN (FEIN with a three-digit sequence number) | MyTax Illinois |
| Unemployment insurance | Illinois Department of Employment Security | Account number issued at registration | MyTax Illinois |
| Sales tax | Illinois Department of Revenue | Sales tax Certificate of Registration | MyTax Illinois |
Form REG-1, the Illinois Business Registration Application, filed through MyTax Illinois, registers the business for its Department of Revenue tax types, and IDOR says the same MyTax Illinois registration can also be used to register with IDES for unemployment insurance and with the Illinois Liquor Control Commission.
After you register for sales tax, Illinois issues a Certificate of Registration showing your Illinois Account ID, an eight-digit number written XXXX-XXXX. It is not your EIN. The certificate must be displayed at the place of business it covers, and you can print it from MyTax Illinois.
Illinois withholding returns, Form IL-941, are tied to your federal EIN plus a three-digit sequence number. The sequence number is 000 unless the Department of Revenue assigned a different one when you registered.
Also on the Illinois list
- Register with the Illinois Department of Revenue through MyTax Illinois. The EIN is required to open the account.
- Register with the Illinois Department of Employment Security before your first payroll; unemployment insurance is handled separately from the revenue account.
Agency sites checked November 1, 2026 · All 50 states
What is different about Illinois
- Illinois charges LLCs and partnerships a Personal Property Replacement Tax on income, on top of the tax the owners pay personally. Most states tax a pass-through entity once at the owner level, so an Illinois LLC has a state filing obligation its equivalent in another state simply does not have.
- The Illinois annual report is due before the first day of the month the LLC was formed in, so every company has its own deadline rather than a single statewide date. Owners who move from another state routinely miss the first one.
- The Department of Business Services issues a file number for the company. It appears on the formation paperwork and is not a tax ID of any kind.
- Illinois tax registration is one application, Form REG-1, filed through MyTax Illinois. It opens sales tax, withholding and the replacement tax account together and asks for the federal EIN and the Secretary of State file number, so both have to exist before the state side can start.
- Illinois has no general state business license, but Chicago and many suburbs license businesses locally, and the state requires a separate employer account with the Department of Employment Security the first time wages are paid. New Illinois owners often finish the Secretary of State and Revenue steps and still have two registrations left.
Before you apply
The SS-4 must match the Illinois Secretary of State, Department of Business Services filing; its file number is a state index, not a tax ID.
Illinois EIN questions
How do I get an EIN number in Illinois?
File IRS Form SS-4 after the Illinois Secretary of State, Department of Business Services approves any formation filing; there is no Illinois EIN application. Form REG-1, the Illinois Business Registration Application, filed through MyTax Illinois, registers the business for its Department of Revenue tax types, and IDOR says the same MyTax Illinois registration can also be used to register with IDES for unemployment insurance and with the Illinois Liquor Control Commission.
Does Illinois give employers a separate withholding number?
No. The Illinois Department of Revenue identifies withholding accounts by the federal EIN (the FEIN with a three-digit sequence number), so the account you open in MyTax Illinois is keyed to the nine digits the IRS issued. That makes the EIN the thing to have before the first Illinois payroll.
Where do I register for Illinois unemployment insurance?
With the Illinois Department of Employment Security, online through MyTax Illinois. The account is separate from the federal EIN, which the registration asks for.
Do I need an Illinois sales tax Certificate of Registration?
Only if you sell what Illinois taxes. The Illinois Department of Revenue issues it through MyTax Illinois, and your returns are filed under its number, not the EIN.
Is there an Illinois EIN or Illinois tax ID number?
No. The EIN is federal and comes from the IRS. Illinois tax registration, Form REG-1 through MyTax Illinois, asks for that federal EIN along with the Secretary of State file number. The file number identifies the company in state records and is not a tax ID of any kind.
What is the Illinois Personal Property Replacement Tax?
A state tax Illinois charges partnerships, including LLCs taxed as partnerships, on their income, on top of the tax the owners pay personally. Most states tax a pass-through entity once at the owner level, so an Illinois LLC can have a state filing its equivalent elsewhere does not. The replacement tax account opens with the same REG-1 registration as sales tax and withholding.
When is the Illinois LLC annual report due?
Before the first day of the month the LLC was formed in, every year, so each company has its own deadline rather than a single statewide date. It is filed with the Secretary of State under the file number, not the EIN, and owners who move from another state routinely miss the first one.
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.
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Related guides
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Sources
- Illinois Secretary of State, Business Services
- MyTax Illinois
- Illinois Department of Revenue: Registration
- Illinois Department of Revenue: General information
- Illinois Department of Revenue: Il 941 instr
- Illinois Department of Employment Security: Tax employer information
- Illinois Department of Employment Security: Employer
- Illinois Department of Employment Security: Pio 117 (PDF)
You can also apply for an EIN directly with the IRS at irs.gov at no cost.