Existing cross-sectional research suggests associations between physical and sexual abuse in childhood and same-sex sexual orientation in adulthood. This study prospectively examined whether abuse and/or neglect in childhood were associated with increased likelihood of same-sex partnerships in adulthood. The sample included physically abused (N = 85), sexually abused (N = 72), and neglected (N = 429) children (ages 0-11) with documented cases during 1967-1971 who were matched with non-maltreated children (N = 415) and followed into adulthood. At approximately age 40, participants (483 women and 461 men) were asked about romantic cohabitation and sexual partners, in the context of in-person interviews covering a range of topics. Group (abuse/neglect versus control) differences were assessed with cross-tabulations and logistic regression. A total of 8% of the overall sample reported any same-sex relationship (cohabitation or sexual partners). Childhood physical abuse and neglect were not significantly associated with same-sex cohabitation or sexual partners. Individuals with documented histories of childhood sexual abuse were significantly more likely than controls to report ever having had same-sex sexual partners (OR = 2.81, 95% CI = 1.16-6.80, p < or = .05); however, only men with histories of childhood sexual abuse were significantly more likely than controls to report same-sex sexual partners (OR = 6.75, 95% CI = 1.53-29.86, p < or = .01). These prospective findings provide tentative evidence of a link between childhood sexual abuse and same-sex sexual partnerships among men, although further research is needed to explore this relationship and to examine potential underlying mechanisms.