You must keep your records as long as they may be needed for the administration of any provision of the Internal Revenue Code. Generally, this means you must keep records that support items shown on your return until the period of limitations for that return runs out.
The period of limitations is the period of time in which you can amend your return to claim a credit or refund or the IRS can assess additional tax. Table 1 contains the periods of limitations that apply to income tax returns. Unless otherwise stated, the years refer to the period beginning after the return was filed. Returns filed before the due date are treated as being filed on the due date.