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Lost or Misplaced Your EIN | Internal Revenue Service

Find a previously filed tax return for your existing entity (if you have filed a return) for which you have your lost or misplaced EIN. Your previously filed return should be notated with your EIN. Ask the IRS to search for your EIN by calling the Business & Specialty Tax Line at 800-829-4933. The hours of operation are 7:00 a.m. - 7:00 p.m ...