Sibling interactions in old age have received limited attention in social science literature. This article examines the different kinds of relationships which exist between siblings in old age and the ways in which each type meets or ignores the social and psychological needs of older people. Five types of sibling relationships emerged from data collected in open-ended, exploratory interviews with thirty men and thirty women over the age of sixty-five who had at least one living sibling. Each type reflects a discrete pattern of instrumental support, emotional support, and contact, as well as a different degree of closeness, envy, resentment, approval, and involvement with the sibling. The distribution of same-sex and cross-sex dyads among the types suggests gender differences in sibling interactions based on the gender composition of the sibling dyad rather than on the gender of the respondent.