IRS LT18 Notice
Overdue Tax Returns, With a Ten-Day Filing Instruction
The IRS asks for the missing return within 10 days of the letter date. That number is published, and it is short.
What is LT18? LT18 tells you the IRS has not received a response to its previous requests for overdue tax returns.
What This Notice Means
LT18 tells you the IRS has not received a response to its previous requests for overdue tax returns.
The instruction on this notice carries a number, which is unusual for a collection letter and is the reason this page exists: the IRS states to send your completed return to the address on the notice "within 10 days from the date on the letter".
Ten days from the letter date, not from the day it arrived. On a letter that reads like a routine reminder, that is the detail most likely to be missed.
Why You Received This Notice
- 1The IRS states it has not received a response from you to its previous requests for overdue tax returns.
Important Deadline
The IRS states a number here, which most collection notices do not: send your completed return to the address on the notice within 10 days from the date on the letter.
That clock runs from the date printed on the letter. It does not run from the day the envelope was opened.
Separately, if you believe you already filed: the IRS states that if it has been over 10 weeks since you sent the return, send a signed copy again. Those are two different ten-somethings on one notice and they are not related.
What You Should Do
- Read the notice and follow the instructions on it.
- Send the completed return to the address on the notice within 10 days from the date on the letter.
- If you already filed and it has been over 10 weeks, send a signed copy again.
- If you had no employees during the tax period shown on the notice, the IRS says to contact it at the toll-free number on the notice with that information.
Resolution Options That May Help
What NOT to Do
- Do NOT count the 10 days from when the letter arrived. The IRS states "from the date on the letter".
- Do NOT send the return to a general IRS address. The IRS specifies the address on the notice.
- Do NOT resend a return you filed recently. Wait until it has been over 10 weeks, then send a signed copy.
Frequently Asked Questions
How long do I have to send the return?
What if I already filed the return?
What if I had no employees in that period?
Need Help With This Notice?
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Related Notices
Recommended Next Steps
- Find the date printed on the letter and count ten days from it.
- Identify from the notice exactly which return and which tax period is outstanding.
- If the period is one in which you had no employees, that is the specific thing the IRS asks you to call about.
Sources and last reviewed
- Understanding your LT18 notice — Internal Revenue Service, retrieved 2026-08-21
- Publication 15, Circular E, Employer's Tax Guide — Internal Revenue Service, retrieved 2026-08-21
Sourced to primary IRS materials and editorially reviewed on 2026-08-21. Not reviewed by a tax professional. Not tax advice. This page explains a notice in general terms and is not tax or legal advice about your situation. Always use the dates and instructions printed on the notice you actually received. Report a correction.