ORS 316.122: Separate or joint determination of income for spouses in a marriage.

(1) If the federal taxable income of spouses in a marriage (one being a part-year resident and the other a nonresident) is determined on a joint federal return, their taxable income in this state shall be separately determined, unless they elect to file a joint return, in which case their tax on their joint income shall be determined in this state pursuant to ORS 316.037 (3).

      (2) If the federal taxable income of spouses in a marriage (one being a full-year resident and the other a part-year resident) is determined on a joint federal return, their taxable income in this state shall be separately determined, unless they elect to file a joint return, in which case their tax on their joint income shall be determined in this state pursuant to ORS 316.037 (2).

      (3) If the federal taxable income of spouses in a marriage (one being a full-year resident and the other a nonresident) is determined on a joint federal return, their taxable income in the state shall be separately determined, unless they elect to file a joint return, in which case their tax on their joint income shall be determined in this state pursuant to ORS 316.037 (3).

      (4) For purposes of computing the tax of spouses under this section, if one of the spouses is a full-year resident individual, then as used in ORS 316.037 (2) or (3), that spouse’s taxable income derived from Oregon sources is that spouse’s entire federal taxable income, defined in the laws of the United States, with the modifications, additions and subtractions provided in this chapter and other laws of this state applicable to personal income taxation.

      (5) The provisions of ORS 316.367 with respect to joint returns apply if both spouses are part-year residents or full-year nonresidents.