To register an LLC in Illinois, file Articles of Organization (Form LLC-5.5) with the Secretary of State’s Department of Business Services and pay a $150 filing fee. Before you file, you need a compliant name and an in-state registered agent. After you file, you need an EIN, a tax classification decision, and a plan for the annual report that keeps your LLC in good standing.
Pick and Clear a Name
Your LLC’s name must include “Limited Liability Company,” “L.L.C.,” or “LLC” so anyone dealing with the business knows it’s a limited liability entity.1Illinois General Assembly. Illinois Code 805 ILCS 180/1-10 – Limited Liability Company Name It also has to be distinguishable from every business name already on file with the Secretary of State. Distinguishable means more than not identical. Swapping “LLC” for “Limited” or shuffling word order generally won’t be enough, and the Secretary of State makes the call.
Search the state’s Business Entity Search at apps.ilsos.gov before you get attached to a name.2Illinois Secretary of State. Business Entity Search Clearing the state database doesn’t clear you on trademarks. A quick check of the U.S. Patent and Trademark Office’s trademark database is worth the few minutes, because a federal trademark holder can force a rebrand even after Illinois approves your filing.3United States Patent and Trademark Office. Search Our Trademark Database
Appoint a Registered Agent
Every Illinois LLC must continuously maintain a registered agent with a physical street address in the state.4Illinois General Assembly. Illinois Code 805 ILCS 180/1-35 – Registered Office and Registered Agent The agent is who receives lawsuits, state correspondence, and tax notices for the company, and must be available at that address during normal business hours.
You can serve as your own agent if you have an Illinois address and are reliably there during the day. Owners who work remotely or don’t want their home address on public filings often hire a commercial registered agent service instead. Whichever route you pick, keep the role filled. If the agent resigns or the address goes stale and you don’t update the filing, the Secretary of State can administratively dissolve your LLC.
File the Articles of Organization
Form LLC-5.5 is the document that officially creates the LLC. You can file online through the Secretary of State’s website or send a paper form by mail.5Illinois Secretary of State. LLC Articles of Organization The form asks for:
- The LLC name, formatted to meet the naming rules.
- The name and Illinois street address of the registered agent.
- The principal office address, which is where the company keeps its main books and records. This address can be outside Illinois.
- The management structure. You’ll say whether the LLC is member-managed or manager-managed. That choice controls whose names appear on the public filing.
- A statement of purpose. Most filers use a general-purpose statement covering any lawful activity.
- The duration. Most choose perpetual; if you have a specific end date, put it here.
- The effective date. You can start the LLC immediately or pick a future date up to 60 days out, which lets you line up your legal start with a tax year or a project.
Check every field before submitting. A rejected filing means you’re not yet legally formed, which matters if you’ve already started signing contracts or opening accounts in the LLC’s name.
Fees and Processing Times
The filing fee is $150. Expedited processing costs an additional $100.6Illinois Secretary of State. Limited Liability Company Publications and Forms Online filings generally process within a few business days. Mailed applications take ten to fifteen business days. Once approved, you’ll get a stamped copy of your Articles of Organization. Keep that document. You’ll need it to open a business bank account, apply for local permits, and prove the LLC’s existence to vendors and lenders.
Get an EIN
An Employer Identification Number is a nine-digit number the IRS assigns to your business. You need one for federal tax filings, for hiring, and for opening a business bank account. The fastest way to get one is the IRS online application, which issues the number immediately at no cost.7Internal Revenue Service. Get an Employer Identification Number You can also apply by fax or mail using Form SS-4, but expect days to weeks.8Internal Revenue Service. Employer Identification Number Wait until your LLC is officially formed with the state before applying. The IRS expects the entity to already exist.
Put an Operating Agreement in Writing
Illinois doesn’t require an operating agreement, but going without one is a mistake, especially in a multi-member LLC.9Illinois General Assembly. Illinois Code 805 ILCS 180/15-5 – Operating Agreement The statute says members “may” enter one, and the agreement governs everything from profit sharing and voting to what happens when a member wants out. You don’t file it with the state. It’s an internal contract among the owners.
Skip it and your LLC runs on the default rules in the Illinois Limited Liability Company Act. Those defaults are generic and rarely match what the owners actually agreed to. For example, defaults may split profits equally regardless of who put in more capital. An operating agreement lets you override those defaults and put your actual deal on paper. Banks often ask to see one when you open a business account.10U.S. Small Business Administration. Open a Business Bank Account
Choose How the LLC Will Be Taxed
The state doesn’t ask you to pick a tax classification, but the IRS does. By default, a single-member LLC is a “disregarded entity,” meaning the business income flows straight onto your personal return. A multi-member LLC defaults to partnership taxation, with each member reporting their share.11Internal Revenue Service. Limited Liability Company (LLC)
You can elect a different treatment. Filing Form 8832 elects C corporation taxation. Filing Form 2553 elects S corporation taxation. The S-corp election is popular with owners who pay themselves a salary, because it can lower self-employment tax on the remaining distributions. For a calendar-year LLC wanting S-corp status for 2026, Form 2553 is due by March 16, 2026. A newly formed LLC has two months and 15 days from its formation date to file. Miss the window and you usually wait until the next tax year. The right classification depends on your income, whether you have employees, and how you plan to take money out. An hour with a tax professional before you elect anything is usually money well spent.
Stay Compliant After Formation
Filing the Articles is the start of your obligations, not the end. Illinois requires every LLC to file an annual report with the Secretary of State.12Illinois General Assembly. Illinois Code 805 ILCS 180/50-1 – Annual Reports The report is due within the 60-day window before the first day of your anniversary month, meaning the month your Articles were approved. If you filed in September, the window opens in early July and closes before September 1. The report confirms your LLC’s name, registered agent, principal address, and the names of managers or managing members. The current fee is on the Secretary of State’s LLC publications page.
Miss the deadline and you pick up penalties. Miss it long enough and the state administratively dissolves the LLC, which strips its legal standing. You can revive a dissolved LLC, but the name is only reserved for three years. After that, someone else can grab it. Reinstatement takes extra fees and paperwork that a calendar reminder would have prevented.
Illinois Replacement Tax
If your LLC is taxed as a partnership or S corporation, it owes the Illinois Personal Property Replacement Tax at 1.5% of net Illinois income.13Illinois Department of Revenue. Personal Property Replacement Tax This surprises many new owners because it’s separate from the individual income tax members pay on their shares. It’s a tax on the entity, and the LLC files and pays it directly to the Illinois Department of Revenue.
Beneficial Ownership Reporting
You may have read that new businesses have to report their beneficial owners to the federal government under the Corporate Transparency Act. As of March 2025, domestic companies, including Illinois LLCs, are exempt under a FinCEN interim final rule.14FinCEN.gov. Beneficial Ownership Information Reporting The reporting obligation now applies only to foreign entities registered to do business in the United States.15Federal Register. Beneficial Ownership Information Reporting Requirement Revision and Deadline Extension Older guides that tell you to file a BOI report for a domestic Illinois LLC are out of date.