Understanding Your CP01B Notice

What this notice is about

This notice tells you the IRS needs more information from you to process your tax return accurately.

Why we are contacting you

We received your federal income tax return; however, we need more information from you to process it. The notice you received provides two options for responding to this notice:

  1. our secure website or
  2. a toll free IRS telephone number

Both options allow you, as the taxpayer, to verify your identity and allow the IRS to continue processing your tax return.

What this process involves

The best way for you to contact us to provide the information needed to process your return is through our identity verification process described below.

What you should do

  • We highly recommend responding through our secure Identity Verification Service website. It's quick and secure. You will need to have a copy of your most recently filed tax return available to complete the entries.
  • You can also contact us using the toll free number provided in your notice. You will, again, need to have a copy of your most recently filed tax return available. Both options are available even if you haven't filed a return for this year.

How you can learn more about the IRS's identity protection efforts

The IRS is continually looking at ways to increase data security and protect taxpayers' identities. To learn more, view these topics on irs.gov.

Printable samples of this notice (PDF)

Need Help?

  • You can authorize someone to contact the IRS on your behalf.
  • See if you qualify for help from a Low Income Taxpayer Clinic.
  • If you can’t find what you need online, you can call the IRS at the 800, 866, or 888 number listed on the notice.