The IRS uses certified mail when the message is legally important and they need proof you received it

A certified letter from the IRS means the agency is sending you something that requires your attention and creates a legal record. The IRS does not use certified mail for routine notices — they send those by regular mail. When you see that green card in your mailbox, it signals that the IRS is making a formal demand, asking you to respond by a specific date, or notifying you of a decision that affects your taxes or refund.

Certified mail with return receipt gives the IRS proof that you got the letter. This matters because tax law has deadlines. If you miss a deadline to respond to an IRS notice, you can lose your right to challenge the agency's decision or to file an appeal. The IRS sends certified mail partly to protect itself — and partly to protect you, because it proves they reached you.

Key Takeaways

  • The IRS sends certified letters only for legally significant notices, such as audit notifications, payment demands, or decisions on appeals.
  • Certified mail creates a legal record that you received the letter, which matters because tax deadlines are strict and missing them can cost you.
  • You must sign for a certified letter or pick it up from the post office; refusing it does not stop the IRS deadline from running.
  • If you receive a certified letter from the IRS, read it carefully, note any deadline printed on it, and keep the letter and the green receipt card together.

Common reasons the IRS sends certified mail

The IRS sends certified letters for notices that require you to take action or that inform you of a significant decision. An audit notice — formally called a Letter 556 or similar — arrives by certified mail because you must respond within a set number of days, usually 30. If you do not respond, the IRS can assess taxes against you without hearing your side.

A Notice of Deficiency (also called a 90-day letter) is sent certified because it tells you the IRS has decided you owe additional tax and gives you 90 days to file a petition in Tax Court if you disagree. Miss that deadline and you lose the right to go to court. The IRS also sends certified mail for payment demands, notices of intent to levy (seize your bank account or wages), and appeal decisions. Each of these carries a deadline or a consequence if you ignore it.

Some certified letters are informational — for example, notifying you that your refund was reduced because you owe a debt to another agency. Even when the letter is not demanding action, the IRS uses certified mail to prove they told you something important.

What happens if you refuse or do not pick up the letter

Refusing a certified letter or leaving it unclaimed at the post office does not stop the IRS deadline. The IRS can claim "constructive receipt" — meaning they tried to deliver it and you refused it — and the deadline still runs. If the letter said you have 30 days to respond, those 30 days start whether you sign for it or not.

If you do not pick up a certified letter, the post office will return it to the IRS after holding it for a set period (usually 15 days). The IRS then has proof they attempted delivery. At that point, the agency may proceed without your input — issuing an assessment, denying your appeal, or moving forward with collection action.

The safest approach is to sign for the letter or pick it up promptly. If you are not home when the postal carrier arrives, you can go to the post office and collect it yourself. Do not ignore the green card left in your mailbox.

How to respond to an IRS certified letter

First, open the letter and read it completely. The IRS notice will state what it is about, what you allegedly owe or what the agency is asking you to do, and the deadline for your response. Write down that deadline on a calendar or set a phone reminder — missing it can be costly.

The letter will also tell you how to respond. Some notices ask you to send documents by mail. Others direct you to call a phone number or visit an IRS office. A few allow you to respond online through the IRS website. Follow the instructions in the letter exactly. If the letter says to send documents by a certain date, send them early enough that they arrive before the deadline; do not mail them the day before.

Keep the original certified letter and the green receipt card together in a safe place. If you later dispute what happened or need to prove you received the notice, you will need both. Take photos or make copies before you file them away.

When to seek help with a certified letter

If you do not understand what the letter is asking for, or if you believe the IRS made an error, you have options. You can contact the IRS directly using the phone number in the letter. You can also work with a tax professional — a CPA, enrolled agent, or tax attorney — who can read the letter and advise you on how to respond.

If the letter is about an audit and you have records to support your position, a tax professional can help you organize those records and submit them to the IRS. If the letter is a Notice of Deficiency and you disagree with the IRS's decision, a tax attorney can advise you on whether filing a Tax Court petition makes sense for your situation.

Do not ignore the letter or assume it will go away. The IRS has significant power to collect taxes, and certified mail is how they formally notify you before taking action. Responding — even if your response is "I disagree" — is always better than silence.

Frequently Asked Questions

Can the IRS send a certified letter about a refund?

Yes, but usually only if the IRS is reducing your refund or denying it entirely. For example, if you owe child support or a federal debt, the IRS may use certified mail to notify you that your refund was offset. A routine refund notice goes by regular mail.

What if I moved and the certified letter was returned to the IRS?

The IRS deadline may still run. If you moved, file a change of address with the post office and the IRS. If you receive a letter after moving, contact the IRS immediately to explain the delay and ask whether the deadline can be extended. Some deadlines are strict, but the IRS has discretion in certain situations.

Do I have to sign for the certified letter in person?

No. You can authorize someone else to sign for it, or you can pick it up at the post office yourself. The key is that the letter must be received — either by you, by someone at your address, or by you collecting it from the post office.

What if the certified letter says I owe money I do not think I owe?

Do not ignore it. Read the letter carefully to understand what the IRS claims you owe and why. If you disagree, respond by the deadline explaining your position and providing supporting documents. If the letter is a Notice of Deficiency, you have 90 days to file a petition in Tax Court.