How far back do I need to file unfiled tax returns?

The IRS's general policy is to require the last 6 years of unfiled returns to be in compliance. This is outlined in IRS Policy Statement 5-133 and Internal Revenue Manual 1.2.14.1.18. However, there are situations where the IRS may require more or fewer years: If you have SFRs (Substitute for Returns) filed by the IRS, you generally need to file all years with SFRs. If you're applying for an installment agreement or OIC, the IRS typically requires all returns for the last 6 years. If you're in a high-income category or the IRS suspects fraud, they may require all unfiled years. If the IRS hasn't contacted you about specific years beyond 6, you may not need to file them. Priority order for filing: file the most recent years first (they have the most impact on current compliance), then work backward. For years within the 3-year refund window, file immediately to preserve refunds. A tax professional can pull your IRS transcripts and determine exactly which years need to be filed and negotiate with the IRS if more than 6 years are demanded.