To study the influence that community settings have upon peer relationships and social behavior, 81 mentally disabled (retarded and emotionally disturbed retarded) adults were observed in their intermediate care residential facility and in one of four workshop programs. In summary, Ss tended to have more extensive affiliation and to aggregate more in their workshops than in their home, though intense relationships tended to be as likely in either setting. It was also possible to classify a S's setting by simply knowing his or her behavior. Findings suggested the importance of the social ecology for successful adaptation of mentally disabled adults in community facilities. (DLS)