Phenomenology and family history in 21 clinically referred children and adolescents with obsessive compulsive disorder are described. Each child and family participated in a standard clinical psychiatric assessment. The most frequently reported symptoms were repeating rituals, washing, ordering and arranging, checking, and contamination concerns. Controlling behaviors involving other family members were seen in 57% of the patients. Associated psychopathology was common: 38% received an anxiety disorder diagnosis; 29% received a mood disorder diagnosis; tics were observed in 24%. Fifteen (71%) of the children had a parent with either obsessive compulsive disorder (N = 4) or obsessive-compulsive symptoms (N = 11). The clinical and research implications of these findings are discussed.