Illinois New Employer Registration

Last reviewed: July 2026

Hiring your first employee in Illinois means opening accounts with two state agencies that don't talk to each other. Skip one and you'll find out the hard way, usually when a quarterly filing comes due and there's no account number to put on it. Here is the registration process laid out in order, with the exact agencies and links you need.

Step 1: Get Your Federal EIN

Every registration below asks for a federal Employer Identification Number, so start there. Apply free at IRS.gov and the number is issued the moment you finish the online application, usually in under fifteen minutes. Keep it handy; you'll type it into both Illinois systems next.

Step 2: Open a MyTax Illinois Withholding Account

The Illinois Department of Revenue manages state income tax withholding through its online portal, MyTax Illinois (mytax.illinois.gov). Registering here gets you a withholding account number, which you need before you can legally withhold and remit Illinois income tax from an employee's paycheck.

To register, you'll provide:

• Your federal EIN
• Business legal name, entity type, and mailing address
• The date you first paid (or expect to pay) Illinois wages
• Owner or officer contact information

Most accounts activate within a few business days of submitting the online form. Once active, this is where you'll file quarterly Form IL-941 returns and, later, transmit annual W-2 data.

Step 3: Register With IDES for SUI

Separately, register with the Illinois Department of Employment Security (IDES) for a state unemployment insurance account, using its TaxNet portal. You become a liable employer once you either pay $1,500 or more in wages during a single quarter, or employ someone for 20 weeks in a calendar year, and registration is due within 30 days after that. In practice, register as soon as you hire.

IDES registration asks for your EIN, entity details, NAICS industry code, and Social Security numbers for owners or officers. Once processed, IDES assigns an employer account number in the format XXX-XXXX-X, along with your initial SUI rate. New employers pay the standard 2026 rate of 3.350% on the first $14,250 of each employee's wages, and that rate is recalculated after roughly three years of claims history.

Step 4: Set Up New Hire Reporting

Federal law requires every new hire to be reported to the state within 20 days of their start date. In Illinois, that report goes through the Illinois New Hire Directory, and you'll need each employee's name, address, Social Security number, and hire date, taken from their completed W-4 and IL-W-4 forms. Our federal new hire reporting guide covers the underlying rule and the penalties for skipping it.

Build this into your onboarding checklist rather than treating it as a separate task. If you're setting up withholding for the first time, our W-4 helper and paycheck calculator can confirm the numbers before the first payroll goes out.

What You'll Have When You're Done

By the end of this process you should have a federal EIN, an active MyTax Illinois withholding account, an IDES employer account number with an assigned SUI rate, and a new hire reporting habit in place for every future hire. That's the full registration picture for a first-time Illinois employer.

Frequently Asked Questions

If juggling two agencies and their separate deadlines sounds like more than you want to manage by hand, software built for this can help. Gusto walks new employers through Illinois-specific registration questions, keeps your withholding and SUI accounts synced to current rates, and files IL-941 and UI-3/40 reports on time without you tracking the dates yourself.