IRS Notice Codes Guide
Every IRS letter has a code — CP## or Letter #### — printed in the top right corner. The code, not the tone of the letter, tells you what the IRS actually wants: information, money, identity verification, or nothing at all. This guide decodes the notices immigrant taxpayers see most, what each deadline really means, and which letters are about your ITIN rather than your taxes.
The three rules for any IRS letter
- Read it and keep it. The IRS asks you to review the notice carefully and keep it for your records. If it asks for a response, act by the due date printed on it — replying on time preserves your appeal rights.
- If you agree, you usually don’t need to reply unless the notice specifically asks. If you disagree, follow the dispute instructions and respond before the due date.
- Verify before you pay. The IRS initiates contact by mail — never by email, text, or social media, and never demanding gift cards. Suspicious letter? Call 800-829-1040.
Notice codes covered
- CP01 — IRS CP01 Notice — Identity Theft Alert
- CP14 — IRS CP14 — Balance Due Notice (You Owe Taxes)
- CP2000 — IRS CP2000 — Underreporter Notice (Income Mismatch)
- CP501 — IRS CP501 — Reminder Notice (Balance Owed)
- CP14H — IRS CP14H — Shared Responsibility Payment Notice (ACA)
- Letter5821 — IRS Letter 5821 — Your ITIN Has Expired
The ITIN notice family
Five notices deal with your ITIN itself, not with money owed:
| Code | What it means | What to do |
|---|---|---|
| CP565 | Your ITIN was assigned | Keep the notice — it’s your proof of the number |
| CP566 | The IRS needs more information on your W-7 | Respond with the requested documents by the due date |
| CP567 | Your W-7 application was rejected | Read the reason; fix and reapply |
| CP48 | Your ITIN is expiring | Renew before filing season |
| Letter 5821 | Your ITIN has expired | Renew now — refunds freeze until you do |
The balance-due escalation track
CP14 → CP501 → CP503 → CP504. Each step adds urgency; CP504 is the intent-to-levy stage where the IRS can take your state refund. At any step you can stop the train by paying or by setting up a payment plan online — ITIN filers qualify the same as everyone else.
Last verified: 2026-06-11. Sources: IRS — Understanding your notice or letter, IRS — Online Payment Agreement.
General procedural information for educational purposes. Not legal, tax, or immigration advice. Laws and fees change — verify with the issuing agency before taking action. For case-specific guidance, consult a licensed tax professional, enrolled agent, or CPA.
Related procedural information
- ITIN — file taxes without SSN — required for federal and most state filings without SSN
- ITIN-friendly business banking — for self-employment and freelance income
- Form an LLC to structure your business income — pass-through tax treatment for ITIN holders
- State driver’s license requirements (DMV) — license status affects residency for state tax
- Find a CPA or enrolled agent — for cross-border or treaty filings