26 CFR § 1.152-2 - Rules relating to general definition of dependent.
(1) Except as provided in subparagraph (2) of this paragraph, to qualify as a dependent an individual must be a citizen or resident of the United States or be a resident of the Canal Zone, the Republic of Panama, Canada, or Mexico, or, for taxable years beginning after December 31, 1971, a national of the United States, at some time during the calendar year in which the taxable year of the taxpayer begins. A resident of the Republic of the Philippines who was born to or legally adopted by the taxpayer in the Philippine Islands before January 1, 1956, at a time when the taxpayer was a member of the Armed Forces of the United States, may also be claimed as a dependent if such resident otherwise qualifies as a dependent. For definition of “Armed Forces of the United States,” see section 7701(a)(15).
(i) For any taxable year beginning after December 31, 1957, a taxpayer who is a citizen, or, for any taxable year beginning after December 31, 1971, a national, of the United States is permitted under section 152(b)(3)(B) to treat as a dependent his legally adopted child who lives with him, as a member of his household, for the entire taxable year and who, but for the citizenship, nationality, or residence requirements of section 152(b)(3) and subparagraph (1) of this paragraph, would qualify as a dependent of the taxpayer for such taxable year.
(ii) Under section 152(b)(3)(B) and this subparagraph, it is necessary that the taxpayer both maintain and occupy the household. The taxpayer and his legally adopted child will be considered as occupying the household for the entire taxable year of the taxpayer notwithstanding temporary absences from the household due to special circumstances. A nonpermanent failure to occupy the common abode by reason of illness, education, business, vacation, military service, or a custody agreement under which the legally adopted child is absent for less than six months in the taxable year of the taxpayer shall be considered temporary absence due to special circumstances. The fact that a legally adopted child dies during the year shall not deprive the taxpayer of the deduction if the child lived in the household for the entire part of the year preceding his death. The period during the taxable year preceding the birth of a child shall not prevent such child from qualifying as a dependent under this subparagraph. Moreover, a legally adopted child who actually becomes a member of the taxpayer's household during the taxable year shall not be prevented from being considered a member of such household for the entire taxable year, if the child is required to remain in a hospital for a period following its birth and if such child would otherwise have been a member of the taxpayer's household during such period.
(iii) For purposes of section 152(b)(3)(B) and this subparagraph, any child whose legal adoption by the taxpayer (a citizen or national of the United States) becomes final at any time before the end of the taxable year of the taxpayer shall not be disqualified as a dependent of such taxpayer by reason of his citizenship, nationality, or residence, provided the child lived with the taxpayer and was a member of the taxpayer's household for the entire taxable year in which the legal adoption became final. For example, A, a citizen of the United States who makes his income tax returns on the basis of the calendar year, is employed in Brazil by an agency of the United States Government. In October 1958 he takes into his household C, a resident of Brazil who is not a citizen of the United States, for the purpose of initiating adoption proceedings. C lives with A and is a member of his household for the remainder of 1958 and for the entire calendar year 1959. On July 1, 1959, the adoption proceedings were completed and C became the legally adopted child of A. If C otherwise qualifies as a dependent, he may be claimed as a dependent by A for 1959.
(1) For purposes of determining the existence of any of the relationships specified in section 152 (a) or (b)(1), a legally adopted child of an individual shall be treated as a child of such individual by blood.
(2) For any taxable year beginning after December 31, 1958, a child who is a member of an individual's household also shall be treated as a child of such individual by blood if the child was placed with the individual by an authorized placement agency for legal adoption pursuant to a formal application filed by the individual with the agency. For purposes of this subparagraph an authorized placement agency is any agency which is authorized by a State, the District of Columbia, a possession of the United States, a foreign country, or a political subdivision of any of the foregoing to place children for adoption. A taxpayer who claims as a dependent a child placed with him for adoption shall attach to his income tax return a statement setting forth the name of the child for whom the dependency deduction is claimed, the name and address of the authorized placement agency, and the date the formal application was filed with the agency.
(3) The application of this paragraph may be illustrated by the following example:
(4) For purposes of determining the existence of any of the relationships specified in section 152 (a) or (b)(1), a foster child of an individual (if such foster child satisfies the requirements set forth in paragraph (b) of § 1.152-1 with respect to such individual) shall, for taxable years beginning after December 31, 1969, be treated as a child of such individual by blood. For purposes of this subparagraph, a foster child is a child who is in the care of a person or persons (other than the parents or adopted parents of the child) who care for the child as their own child. Status as a foster child is not dependent upon or affected by the circumstances under which the child became a member of the household.
(d) In the case of a joint return it is not necessary that the prescribed relationship exist between the person claimed as a dependent and the spouse who furnishes the support; it is sufficient if the prescribed relationship exists with respect to either spouse. Thus, a husband and wife making a joint return may claim as a dependent a daughter of the wife's brother (wife's niece) even though the husband is the one who furnishes the chief support. The relationship of affinity once existing will not terminate by divorce or the death of a spouse. For example, a widower may continue to claim his deceased wife's father (his father-in-law) as a dependent provided he meets the other requirements of section 151.