Filing back taxes is similar to filing your current income tax return except that there are some factors you need to consider. However, this process isn’t as complicated as you might think. When filing back taxes, the first thing you need to do is track down all the missing documents you need and request a copy from the IRS using the Request for Transcript of Tax Return or form 4506-T. Once you have all the missing documents, you must download original tax forms from the IRS web site in order to file your back tax returns. For filing back taxes, you also need the W-2 or 1099 forms which are also available on the IRS web site or other authorised web sites. After completing the initial preparation, you can now prepare your late income tax returns by filling the necessary forms with the information you have. Double check every entry you make for any errors, possible deductions, and payments. Then you can mail your late income tax return to the address indicated on Form 1040.