An IRS audit follows a structured legal process — and understanding each stage is critical to protecting your rights and achieving the best possible outcome. When the IRS selects your return for examination, it triggers a series of procedural steps governed by the Internal Revenue Manual (IRM) and the Taxpayer Bill of Rights. The process begins with a written notice and moves through document production, agent review, and a formal report — with multiple opportunities along the way to contest the IRS's position. For the majority of taxpayers who receive professional representation immediately, the audit process is manageable. The outcomes that damage taxpayers most severely almost always result from missed deadlines, inadequate documentation, or attempts at self-representation that inadvertently expanded the audit's scope. This guide walks through every stage of the process so you know exactly what to expect — and what to do at each step. IRS audit defense Key Takeaways IRS audits begin with a written notice and typically take 3–6 months (correspondence) to 12–36 months (field) to resolve. You have the right to professional representation from the very first contact — file Form 2848 before responding. The IRS issues a formal Revenue Agent's Report (RAR) proposing any changes — this is not final and is contestable. If you disagree with the RAR, you have 30 days to request Appeals — approximately 70% of cases settle at this stage. Missed deadlines are the most costly audit mistakes: the 30-day and 90-day letters have strict consequences if ignored. What Types of IRS Audits Are There — and Does the Process Differ? Audit Type Conducted By Format Typical Duration Common Triggers Correspondence Audit AUR Unit / Campus Center Mail only — letter exchange 3–6 months 1099 mismatches, math errors, missing forms Office Audit Revenue Agent In-person at IRS office 6–12...