The Internal Revenue Service provides instructions on its website for finding a previously issued self-employed tax ID number. The agency recommends that individuals search through existing records for the missing information. If that fails, individuals can contact the IRS Business and Tax Line for assistance.
The IRS issues a computer notification to taxpayers to confirm the issuance of an Employer ID Number, and this notification is one place to find the number. Individuals who have used their EIN to open a bank account can contact the bank to arrange to get the number from its paperwork on file. Likewise, local and state agencies usually keep records of official documents that contain this vital information.