You should apply for an EIN early enough to have your number when you need to file a return or make a deposit. You can get an EIN quickly by applying online, or by calling the Tele-TIN phone number for your state. If you prefer, you can fax a completed Form SS-4 to the service center, and they will respond with a return fax in about one week. If you do not include a return fax number, it will take about two weeks. If you apply by mail, send your completed Form SS-4 (PDF) at least four to five weeks before you need your EIN to file a return or make a deposit.

If you don't have your EIN by the time a return is due, write "Applied for" and the date you applied in the space shown for the number. Do not use your social security number.

If you don't have your EIN by the time a deposit is due, send your payment to the service center address for your state. Make your check or money order payable to Internal Revenue Service and show your name (as shown on the SS-4), address, kind of tax, period covered, and the date you applied for your EIN.

Read Publication 1635, Understanding Your EIN (PDF).