IRS Letter 105C: Claim disallowed
Quick answerThe IRS fully disallowed a claim you filed — for example an amended return, refund claim or penalty abatement request.
Letter / notice105C
MeaningClaim disallowed
Action needed?Yes — see steps
What happens next
You can appeal, and you generally have 2 years from the letter date to sue for a refund in court.
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What you should do
- Read the reason for disallowance
- Send more evidence or request an Appeals review as the letter explains
Scam check: the IRS first contacts you by mail. Use only the phone numbers printed on your letter or on IRS.gov — never ones from a text, email or unofficial site.
Frequently asked questions
What does IRS Letter 105C mean?
The IRS fully disallowed a claim you filed — for example an amended return, refund claim or penalty abatement request.
What should I do?
Read the reason for disallowance Send more evidence or request an Appeals review as the letter explains
How long does it take?
You can appeal, and you generally have 2 years from the letter date to sue for a refund in court.
Sources
- IRS: Understanding your IRS notice or letter
- IRS: Get Transcript
- Taxpayer Advocate Service (independent help inside the IRS)
Written by the editorial team and checked against the official sources above. See our editorial policy.
By the TranscriptCodes Editorial Team · Last reviewed 2026-11-12.