If you previously applied for and received an Employer Identification Number (EIN) for your business, but have since misplaced it, try any or all of the following actions to locate the number: Find the computer-generated notice that was issued by the IRS when you applied for your EIN. This notice is issued as a confirmation of your application for, and receipt of an EIN. If you used your EIN to open a bank account or apply for any type of state or local license, you should contact the bank or agency to secure your EIN. 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 a.m. - 7 p.m. local time, Monday through Friday. An assistor will ask you for identifying information and provide the number to you over the telephone, as long as you are a person who is authorized to receive it. Examples of an authorized person include, but are not limited to, a sole proprietor, a partner in a partnership, a corporate officer, a trustee of a trust, or an executor of an estate. Related A-Z index for business Employer ID numbers Small business forms and publications Industries Professions Small business online learning Operating a business Self-employed individuals tax center Starting a business