The final sample consisted of 209 cases and 209 controls. Interviews with the mothers obtained data on family circumstances, parents' childhoods, child characteristics, and the mother's perception of her child's temperament. Discriminant analysis suggested interrelationships among the case groups, and cluster analysis identified three cohesive groups according to symptom severity. Case children differed from control children not only in presenting symptoms but in a variety of ecological characteristics. Families of children with a social illness were experiencing more stress than families of children with nonfatal acute medical conditions. The clusters identified in this study provide a matrix for organizing data from families whose children suffer pediatric social illnesses. This will facilitate focusing on specific aspects of family functioning that require therapeutic attention. 5 tables and 24 references.