On the basis of an adult model of sibling attachment, I hypothesized that the well-being of older persons depends on their perception of the closeness of the sibling bond, on their perception of any disruption of that bond, and on the sex combination of the siblings being considered. In all, 83 persons, aged 61 to 91 years, were interviewed about their relationships with each of their living siblings. They rated their feelings of closeness, conflict or rivalry, and indifference to the sibling. A measure of depression was used as the indicator of well-being. Separate correlational analyses were carried out for the four sex combinations of siblings. Closeness of the bond to a sister (by both men and women) was related to less depression. Also, women's perceptions of conflict and indifference in their relationships with sisters were related to increased depression. Findings are interpreted in terms of attachment theory and sex role expectations.