For tax returns, you can ask the IRS to send you a computer printout of a tax return you filed (called a "return transcript"), or you can ask for a photocopy of the actual return you filed. Transcripts are free, and photocopies cost $39 per year you are requesting. You can order transcripts by filling out Form 4506-T. You can order photocopies by sending in Form 4506.
If you need help reconstructing your tax documents, the IRS issued important guidelines to follow. Although the guidelines were designed for the victims of the Gulf Coast hurricane victims, this IRS guidance actually provides a safe and reliable way to reconstruct your financial situation when important documents have been lost.

