How Many Years Back Does the IRS Go in an Audit? We don't know on it so the IRS usually will start with one year if you get an audit notice and there are multiple years that's an immediate red flag that there's a serious issue generally speaking the IRS is an audit period is a three-year statute of limitations so the IRS generally doesn't go back to more than three years when doing it on it so if you actually went to the IRS and you talked to an auditor and you had them show their initial file when the IRS selects your return for audit what happens is there's a three year comparison of income and certain items that are on the return so the IRS is generally looking form of audits from a three-year perspective, so most audits will go three years now in the case that there's a substantial report underreporting of income then the IRS will go back up to six years if the government feels that the taxpayer has committed fraud then the IRS can technically go back indefinitely but it's only in those cases will they go back longer than the three-year period if there is a substantial understatement then they will go back up to six but generally speaking they keep it within the three-year market so again but they usually do is they'll start with a year they'll see if there's errors in there because the government is not about creating more work for itself than it needs to and then if they find errors in one year they'll open up. The entire your period if they find substantial underreporting of income then they'll open up a six year period but that's generally how long the government is going back when in all its tax returns.