IRS Notice Notice of Deficiency
90-Day Letter
This is your legal right to challenge the IRS in Tax Court before paying. Miss this deadline and you lose that right.
Tax Attorney · Villanova University School of Law · Admitted in Delaware, New Jersey, United States Tax Court
Notice Notice of Deficiency in Plain English
The Notice of Deficiency — the '90-day letter' — is your legal ticket to Tax Court. You have exactly 90 days from the date on the notice to file a petition. Miss it, and the tax is assessed; you must then pay first and sue for a refund in a different court.
Why the IRS sent you a Notice of Deficiency
A CP2000 or examination proposal was not resolved and the IRS proceeded to assessment.
You failed to respond to a 30-day letter and the case advanced automatically.
The IRS is asserting fraud, substantial-omission, or foreign-account penalties requiring a statutory notice.
What Happens If You Ignore Notice Notice of Deficiency
If you don't petition Tax Court within 90 days, you must pay first and sue for a refund later. You lose valuable rights.
Every day you wait, penalties compound, interest accrues, and your options shrink. The IRS does not negotiate well with silence — they escalate.
What To Do About Notice Notice of Deficiency
This deadline is absolute. Contact us immediately to evaluate whether Tax Court is the right option for you.
- 1
Diary the 90-day deadline immediately — it is the strictest deadline in tax law and cannot be extended, even by one day.
- 2
File a Tax Court petition (Form 2) even if you plan to settle — filing preserves the pay-later, litigate-first path.
- 3
Once petitioned, the case is routed to IRS Appeals for settlement before ever seeing a judge; ~90% settle at that stage.
- 4
Simultaneously consider a CDP request if a levy is threatened on the same period — the two protections stack.
A Senior Tax Attorney's Take on Notice of Deficiency
A Tax Court petition is the last free pass in the entire IRS process — pay nothing up front, litigate in the taxpayer's home court, and use Appeals for a settlement audition. Missing the 90-day window converts a $10K case into a $10K case plus federal district court filing fees and collateral liens.
Call (877) 829-5267Costly Mistakes People Make With Notice Notice of Deficiency
Calling the IRS to 'work it out' during the 90-day window and letting the deadline slip while waiting for a callback.
Filing a petition on day 91 — the U.S. Tax Court has no jurisdiction to hear it, no matter the merits.
Confusing this with a state tax deficiency notice; state deadlines are separate and usually shorter.
IRS Notices Related to Notice of Deficiency
These are the notices the IRS most often sends before, after, or alongside a Notice of Deficiency. Read the related ones to understand where you are in the collection sequence.
Tax Resolution Services That Resolve a Notice of Deficiency
Senior tax attorneys at McCauley Law Offices use these strategies to stop, settle, or unwind a Notice of Deficiency notice.
Primary Sources & Authority
We cite the underlying IRS publications and statutes so you can verify everything on this page.