IRS NOTICE REFERENCE
90 Day Notice of Deficiency
Letter 3219, Notice of Deficiency (also referred to as a 90-Day Letter), is a taxpayer’s legal notice that the IRS is proposing a deficiency. These letters provide taxpayers with information about their right to challeng…
General information only. Not legal or tax advice.
Notice details
- Notice code
- 90 Day Notice of Deficiency
- Category
- Underreporter / income matching
- Severity tier
- Tier 4 — Escalation warranted. The notice involves collection enforcement, appeals rights, or significant penalty exposure.
- Governing law
- §6212; §6213 (Internal Revenue Code sections)
- Statutory response window
- 90-day window — always confirm the exact deadline against the date printed on your notice.
- Escalation flag
- This notice carries a forfeitable right, a hard statutory deadline, or criminal-preparer risk. It is flagged for escalation in the TaxRiskOS workflow.
- Source
- IRS Taxpayer Advocate Service
What this notice is
Letter 3219, Notice of Deficiency (also referred to as a 90-Day Letter), is a taxpayer’s legal notice that the IRS is proposing a deficiency. These letters provide taxpayers with information about their right to challenge proposed IRS adjustments in the United States Tax Court by filing a petition within 90 days of the date of their notice (150 days if you reside outside the United States).
Source: IRS Taxpayer Advocate Service. Reproduced for reference. General information — not legal or tax advice.
Governing IRS procedure (Internal Revenue Manual)
The IRS’s own internal procedures for handling this notice type are documented in the Internal Revenue Manual:
- IRM 4.19.3 — 4.19.3 IMF Automated Underreporter Program
- IRM 4.19.2 — 4.19.2 IMF Automated Underreporter (AUR) Control
Reference to published IRS procedure. General information — not legal or tax advice.
Official IRS reference
Read the official notice page on IRS.gov: https://www.taxpayeradvocate.irs.gov/notices/90-day-notice-of-deficiency/
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
Check this notice’s deadline (free tool)