This document contains final regulations relating to the allocation and apportionment of the deduction for charitable contributions allowed under sections 170, 873(b)(2), and 882(c)(1)(B) and the deduction for charitable contributions allowed under an income tax treaty. These regulations apportion the deduction for charitable contributions on the basis of income from sources within the United States. These regulations affect individuals and corporations that make contributions to charitable organizations and that have foreign source income and calculate their foreign tax credit limitations under section 904.