The Internal Revenue Service keeps copies of all versions of tax Form 1040 for up to six years. After that time, as required by law, it destroys them, according to the IRS. The IRS may maintain other tax forms for more than six years.
Along with copies of the 1040 forms, including Forms 1040A and 1040EZ, the IRS keeps all documentation submitted with the forms, including W-2s and 1099 forms. Taxpayers who want copies of their old tax returns must pay $50 per copy, as of 2015. However, taxpayers affected by disasters may be able to get copies for free, and transcripts of past tax returns are also free, as the IRS explains.