Register with IDES when you first hire employees in Illinois. You'll receive an employer account number and an initial SUI rate. File quarterly UI-3/40 reports. Registration and filing are done online through MyTax Illinois.
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What Is IDES?
The Illinois Department of Employment Security (IDES) is the state agency that administers unemployment insurance in Illinois. Every employer who hires workers in the state must register with IDES, contribute to the unemployment insurance trust fund, and file quarterly wage reports.
IDES is separate from the Illinois Department of Revenue (IDOR), which handles state income tax withholding. As an Illinois employer, you'll interact with both agencies, but they serve different purposes and operate different online portals.
This guide walks you through the IDES registration process, what you'll receive after registering, and the ongoing filing obligations that come with being an Illinois employer.
When You Must Register
Illinois law requires employers to register with IDES within 30 days of becoming a liable employer. You become a liable employer when either of these conditions is met:
- Wage threshold: You pay wages of $1,500 or more in a single calendar quarter, OR
- Employment duration: You employ at least one worker for 20 weeks in a calendar year (the weeks do not need to be consecutive)
Once either threshold is triggered, you must register with IDES within 30 days. Most new employers hit one of these thresholds quickly, so in practice, you should plan to register as soon as you make your first hire.
What You Need Before Registration
Before you begin the online registration process, gather the following information:
- Federal Employer Identification Number (EIN) — obtained from the IRS via Form SS-4
- Business entity information — legal name, DBA (if applicable), business address, entity type (LLC, corporation, sole proprietorship, etc.)
- NAICS code — the North American Industry Classification System code that describes your primary business activity
- Owner/officer Social Security Numbers — SSNs for all owners, partners, or corporate officers
- Date of first payroll — the date you first paid (or will pay) wages to an employee in Illinois
- Number of employees — current or expected employee count
- Business formation date — when the business was legally established
How to Register Online
IDES registration is completed online through MyTax Illinois, the secure website maintained by the Illinois Department of Revenue (IDOR) that IDES now uses for all unemployment insurance tax processes. Here's the step-by-step process:
Step 1: Create a MyTax Illinois Account
Go to mytax.illinois.gov and register your new business. MyTax Illinois lets you register with both IDOR and IDES at one time (see the IDES new employer page). Your MyTax Illinois login is how you'll manage all unemployment insurance obligations going forward.
Step 2: Complete the Registration Form
Once logged in, complete the new employer registration form. You'll enter your federal EIN, business entity details, NAICS code, owner/officer information, and date of first payroll. The system will ask about your business type, ownership structure, and whether you acquired the business from a previous employer (which can affect your initial SUI rate).
Step 3: Submit and Receive Your Employer Account Number
After submitting the registration, IDES will process your application and assign you an Illinois employer account number. In most cases, you'll receive confirmation within a few business days. Once it's assigned, you'll be able to view your IDES account in MyTax Illinois.
What You Receive After Registration
After IDES processes your registration, you'll receive the following:
IDES Employer Account Number
Your employer account number follows the format XXX-XXXX-X (three digits, a dash, four digits, a dash, one digit). This number identifies your business in all unemployment insurance filings and correspondence with IDES. Keep it in a safe place — you'll use it on every quarterly report.
Initial SUI Rate Assignment
New employers in Illinois are assigned an initial State Unemployment Insurance (SUI) rate of 3.350%. This rate applies until you build enough experience history for IDES to calculate an experience-based rate, which typically takes about three years of filing history. The rate is applied to taxable wages up to the annual wage base ($14,250 for 2026).
Filing Frequency Information
IDES will confirm your quarterly filing requirement. All Illinois employers file on the same quarterly schedule — there is no option for annual or monthly filing with IDES (unlike some other state agencies).
Filing Requirements
Once registered, your primary ongoing obligation with IDES is filing the UI-3/40 (Employer's Contribution and Wage Report) each quarter. This report serves two purposes: it reports wages paid to each employee, and it calculates your SUI contribution for the quarter.
Quarterly Deadlines
UI-3/40 reports are due on the following dates each year:
- Q1 (Jan–Mar): Due April 30
- Q2 (Apr–Jun): Due July 31
- Q3 (Jul–Sep): Due October 31
- Q4 (Oct–Dec): Due January 31
If the due date falls on a weekend or holiday, the deadline moves to the next business day.
What You Report
Each quarterly UI-3/40 filing includes:
- Total wages paid to all employees during the quarter
- Taxable wages (wages up to the $14,250 annual wage base per employee)
- Individual employee wage detail (name, SSN, wages for each employee)
- SUI contribution amount owed (taxable wages multiplied by your SUI rate)
How to File and Pay
File your UI-3/40 electronically through MyTax Illinois. You can also make SUI contribution payments there. Electronic filing is required for employers with 25 or more employees, but IDES encourages all employers to use MyTax Illinois regardless of size.
MyTax Illinois: One Portal, Two Agencies
One of the most common sources of confusion for new Illinois employers is that two agencies now share one portal. IDES and the Illinois Department of Revenue (IDOR) keep separate accounts and separate returns, but both use MyTax Illinois:
IDES Account
- Agency: Illinois Department of Employment Security (IDES)
- Purpose: Unemployment insurance
- What you file: Quarterly UI-3/40 (wage reports and SUI contributions)
- More information: ides.illinois.gov
IDOR Withholding Account
- Agency: Illinois Department of Revenue (IDOR)
- Purpose: State income tax withholding
- What you file: IL-941 (quarterly withholding returns) and Forms W-2 (filed electronically)
- URL: mytax.illinois.gov
You need an account with both agencies. Your IDES account handles unemployment insurance obligations. Your IDOR account handles state income tax withholding. MyTax Illinois lets you register your new business with both at one time, but each agency assigns its own account and each has its own quarterly return.
New Hire Reporting
In addition to IDES registration, Illinois requires employers to report newly hired and rehired employees to the state. This is a separate obligation from unemployment insurance registration.
Reporting Requirements
- Deadline: Within 20 days of the employee's hire date (or rehire date)
- Information required: Employee name, address, SSN, date of hire, and employer name, address, and EIN — using information from the employee's W-4 and IL-W-4 forms
- Filed with: Illinois Department of Healthcare and Family Services (not IDES)
- How to file: Electronically through the Illinois New Hire Reporting portal, by mail, or by fax
New hire reporting is a federal requirement under the Personal Responsibility and Work Opportunity Reconciliation Act, but each state administers its own program. Illinois routes new hire data through the Department of Healthcare and Family Services, which uses the information to locate parents who owe child support and to detect unemployment insurance fraud.
Common Registration Mistakes
New employers frequently make these mistakes during the Illinois registration process. Avoid them to stay compliant from day one:
1. Registering Late
The most common mistake. Many new employers don't realize they need to register with IDES until after they've been paying employees for several months. By that time, quarterly reports are already overdue and contributions are accruing interest. Register within 30 days of your first hire.
2. Confusing IDES with IDOR
IDES (Department of Employment Security) handles unemployment insurance. IDOR (Department of Revenue) handles income tax withholding. Registering with one does not register you with the other. You need accounts with both agencies.
3. Not Setting Up Both Accounts
Some employers set up an income tax withholding account but never register with IDES for unemployment insurance, or vice versa. The two accounts are separate and each has its own quarterly filing. MyTax Illinois lets you register with both agencies at one time, so complete both during your initial employer setup.
4. Incorrect NAICS Code
Your NAICS code affects your initial SUI rate assignment. Using the wrong code can result in a higher or lower rate than appropriate for your industry. Take the time to identify the correct code at census.gov/naics.
5. Missing Owner/Officer Information
IDES requires SSNs for all owners, partners, and corporate officers. Incomplete submissions will delay processing. Have this information ready before starting the registration.
Frequently Asked Questions
How long does IDES registration take?
Online registration is done through MyTax Illinois, where you can register with IDES and the Illinois Department of Revenue at one time. Once IDES processes your registration, it assigns your employer account number, and you can view the account in MyTax Illinois.
Is there a fee to register with IDES?
No. Registration with IDES is free. Your ongoing costs are the quarterly SUI contributions based on your assigned rate and employee wages.
What if I already have an IDES account from a previous business?
Each business entity requires its own IDES employer account. If you're starting a new business, you need a new registration even if you've had an IDES account before. If you're acquiring an existing business, the previous owner's experience rating may transfer to you under certain conditions — contact IDES for guidance.
Can I register by mail instead of online?
Yes, you can submit a completed and signed Form REG-UI-1 by mail, but online registration through MyTax Illinois is faster and recommended. Paper submissions take longer to process.
What is the new employer SUI rate for 2026?
New employers in Illinois are assigned an initial SUI rate of 3.350%. This rate applies to the first $14,250 of each employee's wages per year. After approximately three years of filing history, IDES will calculate an experience-based rate that may be higher or lower depending on your claims history.
Do I need to register with IDES if I only have 1099 contractors?
No. IDES registration is only required when you have W-2 employees. Independent contractors (1099 workers) are not covered by unemployment insurance. However, be sure your workers are correctly classified — Illinois enforces worker classification rules strictly under the Employee Classification Act.
What happens if I miss a quarterly UI-3/40 filing?
IDES assesses penalties and interest on late filings and unpaid contributions. Repeated late filings can negatively impact your SUI experience rating, potentially increasing your rate. File on time even if you owe nothing for the quarter.
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Disclaimer
This article provides general information about Illinois IDES registration requirements and is current as of February 2026. It is not legal or tax advice. Illinois employment law, SUI rates, and filing requirements are subject to change.
Consult a qualified Illinois attorney, CPA, or payroll professional for advice specific to your situation. For official guidance, visit ides.illinois.gov.