This document contains regulations relating to the depreciation of property subject to section 168 of the Internal Revenue Code (MACRS property) and the depreciation of computer software subject to section 167. Specifically, these regulations provide guidance regarding the additional first year depreciation allowance provided by sections 168(k) and 1400L(b) for certain MACRS property and computer software. The regulations reflect changes to the law made by the Job Creation and Worker Assistance Act of 2002 and the Jobs and Growth Tax Relief Reconciliation Act of 2003. The text of these temporary regulations also serves as the text of the proposed regulations set forth in the notice of proposed rulemaking on this subject in the Proposed Rules section in this issue of the Federal Register.