This document contains final regulations under section 6109 of the Internal Revenue Code (Code) that provide guidance on how the IRS will define the identifying number of tax return preparers and set forth requirements on tax return preparers to furnish an identifying number on tax returns and claims for refund of tax they prepare. Additional provisions of the regulations provide that tax return preparers must apply for and regularly renew their preparer identifying number as the IRS may prescribe in forms, instructions, or other guidance.