VALID › Notice Library › CP518B business notice
In the IRS’s own words · not reviewed by VALID
CP518B notice explained, in the IRS’s own words
This is a final reminder notice that we still have no record that you filed your prior tax returns.
Read the full CP518B page on irs.gov ↗
What this notice is about
This is a final reminder notice that we still have no record that you filed your prior tax returns.
What you need to do
- Send a signed paper tax return with all required schedules.
- Complete and return the Response form enclosed with your notice. Use it to explain one of the following:
- The reason you’re filing late.
- Explain why you believe you don’t need to file or that you already filed and more than four weeks have passed.
- That you filed with a different name or employer ID number (EIN) than the one shown on your notice.
- If you filed within the last four weeks using the same name and EIN shown on your notice, you may disregard this notice.
How to send your information
- Use the enclosed envelope to respond or fax your documents to 855-800-5944 using either a fax machine or online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies.
If we don't hear from you
- We may determine your tax for you. Penalty and interest can continue to accrue.
- If you're owed a refund for the current tax year, or any prior year, it may be delayed because of this unfiled return.
You may want to
- Review the Collection Procedures for Taxpayers Filing and/or Paying Late.
- Verify you filed all your prior returns. Download copies of prior year tax returns and products.
- Check to see that you have enough withholding from your paycheck to pay your taxes. The Tax Withholding Estimator can help.
- Learn more about your payment options if you owe additional taxes on your return.
- Learn more about payment plans and installment agreements.
- Learn more about an Offer in Compromise.
Frequently asked questions
What should I do if I disagree with the notice? (updated July 14, 2026)
Call us at the toll-free number shown on your notice. Have your paperwork ready when you call.
What should I do if I've just filed my tax return?
You don't have to do anything if you filed your tax return within the last 8 weeks.
What should I do if I didn't file my tax return or it's been more than 8 weeks since I filed it? (updated July 14, 2026)
Sign, date and mail us a copy of the tax return with the completed Response form which was included with your notice. Make sure your name, social security number and tax year match on your return and notice.
What happens if I can't pay the full amount I owe when I file my return? (updated July 14, 2026)
You can request a payment plan.
Tips for next year
File your return on time. Consider filing your taxes electronically. Filing online can help you avoid mistakes and find credits and deductions that you may qualify for. In many cases you can file for free.
What to do next
- Write down the date on the letter today.
- Look the number up on irs.gov yourself. Don’t trust a link or phone number from anyone else.
- If it says you owe money or proposes changes to your return, take it to a licensed CPA, EA or tax attorney before that date.
Not advice. Not a filing. Verify with a licensed professional. Rules change by year and facts.