Credits or Refunds, § 6511. If tax has been paid, a taxpayer may file a claim for refund. A claim for a credit or refund must generally be filed within three years from the date the original return was filed or within two years from the date the tax was paid, if later. If no return was filed, the claim must be filed within two years from the date the tax was paid. If a claim for refund is denied by the IRS, the taxpayer can file a suit for refund in U.S. District Court or in Claims Court within two years after the denial of the claim for refund.