Skip to main content

List of IRS CP Notices

Got an IRS CP notice? Look it up here. We explain every CP code — CP2000, CP504, CP3219A and more — plus exactly how to respond to each one.

What Are IRS CP-Series Notices?

Getting mail from the IRS can cause anxiety for many taxpayers, especially when those envelopes have codes such as CP12, CP2000, or CP503 on them. These CP notices, collectively referred to as the CP-Series Notices, are letters that the IRS uses to pass important information about your tax return, payments, or other related matters. To avoid issues with the IRS, you have to learn what these common IRS notices mean, how you can interpret them, and most importantly, how to respond effectively.

CP-Series Notices are a group of standardized letters and notices issued by the IRS to address various issues related to a taxpayer’s individual or business tax return. These notices cover a wide range of topics, including adjustments to your tax return, overdue tax payments, and other discrepancies that may need your attention. Each notice in the CP-Series is designated by a specific code, such as CP2000, CP503, CP12, etc., to help both the IRS and the recipient identify the type of issue being addressed.

Common IRS CP-Series Notices and Their Meanings

Here, we've classified these notices according to the financial/tax issue they're trying to address. They include the following:

Balance Due & Payment Notices

Tax Return & Adjustment Notices

Earned Income Tax Credit (EITC) & Identity Verification Notices

Underreported Income & Audit Notices

Refund Delay & Adjustment Notices

Business & Payroll Tax Notices

How to Respond to CP-Series Notices

Responding to CP-Series Notices is essential to address any discrepancies or issues and avoid potential consequences. Here are the general steps you should take:

Frequently Asked Questions

What should I do if I disagree with the information in a CP-Series Notice?

If you believe the notice is incorrect, respond in writing by the deadline shown and include documentation that supports your position, such as corrected forms or proof of payment. Keep copies of everything you send and a record of how you sent it. Depending on the notice, you may also have formal appeal rights, and a tax attorney can help you present your case.

What happens if I ignore a CP-Series Notice?

Ignoring a CP-Series notice usually leads to escalating consequences. Interest and penalties can continue to grow, and the IRS may move from reminders to enforced collection, such as a federal tax lien or a levy on wages or bank accounts. Some notices also set deadlines to dispute the IRS position, and letting them pass can forfeit your right to challenge the amount.

Can I negotiate the proposed changes in a CP2000 notice?

Yes. A CP2000 is a proposed change based on a mismatch between your return and information the IRS received, not a final bill. If you disagree, you can respond by the deadline with an explanation and supporting documents, and the IRS will review your reply. If you agree only in part, you can say which items you accept and which you contest, and a tax professional can help you frame the response.

How can I set up an installment agreement to pay my tax debt mentioned in a CP-Series Notice?

To set up an installment agreement, follow the instructions provided in the notice or visit the IRS website to explore online payment options and request an installment agreement.

What should I do if I cannot pay the full amount mentioned in a CP503 or CP504 notice?

If you cannot pay the full amount, you may consider setting up an installment agreement or making an offer in compromise (OIC) to settle the debt for less than the full amount. Contact the IRS to discuss these options.

Request a free consultation with our experts today and take the first step towards achieving your goals.

This content was written and reviewed by the licensed tax attorneys at Victory Tax Lawyers, LLP. Our attorneys specialize in IRS tax relief and are licensed members of the California State Bar with a nationwide practice.

Last Reviewed: 2026  ·  Meet Our Attorneys →

Attorney Advertising. Prior results do not guarantee a similar outcome. This website is for informational purposes only and does not constitute legal advice. No attorney-client relationship is formed by viewing or using this website. For legal advice, please schedule a consultation.

© Victory Tax Lawyers © 2026. All rights reserved. Powered by GLP Marketing

Tax Relief

Ready to Resolve Your Tax Issues?

Our experienced tax attorneys have saved clients over $91 million. Get a free, confidential consultation today.

Keep reading our in-depth guides on this topic, or speak with a tax attorney about your situation.

What Our Clients Say

5.0 out of 5 · 73 Google reviews
See all on Google

Live reviews from Victory Tax Lawyers' Google Business Profile (1100 S Robertson Blvd, Los Angeles). Updated Jun 26, 2026.