IRS Letter 3219, also called the Statutory Notice of Deficiency or "90-Day Letter," is the IRS's formal notice that it intends to assess additional tax against you — and it gives you exactly 90 days (150 days if you're outside the US) to file a petition in federal tax disputes to challenge the assessment before paying. Missing this 90-day deadline permanently forfeits your right to challenge the deficiency through the formal dispute process without first paying the full amount. Neil Jesani Tax Resolution's tax professionals experienced in federal tax disputes prepare and file formal dispute petitions and represent clients through trial or settlement. Key Takeaways Letter 3219 is the Statutory Notice of Deficiency (also called the "90-day letter"), representing the IRS's final determination that you owe additional tax You have exactly 90 days (150 days if outside the U.S.) from the date of the letter to file a petition with the federal tax disputes If you do not file a formal dispute petition within the deadline, the IRS will assess the deficiency and begin collection — and you lose your right to judicial review before paying Filing a formal dispute petition does not require you to pay the disputed tax first — this is a critical advantage Professional representation is essential for the formal tax dispute process proceedings due to the complexity of the rules and the stakes involved What Is IRS Letter 3219? IRS Letter 3219, formally known as the Statutory Notice of Deficiency, is one of the most important documents in tax law. Often referred to as the "90-day letter," it is the IRS's formal and final determination that you owe additional tax for a specific tax year. This letter is typically issued after an audit or examination has been completed and either you did not agree with...