Pediatric obsessive-compulsive disorder (OCD) is a chronic, disabling condition that affects both patients and their families. Despite the identification of efficacious treatments (e.g., cognitive-behavioral therapy and selective serotonin reuptake inhibitor medications), not all patients respond fully. The purpose of the present study was to examine whether the amount of family accommodation provided to pediatric patients with OCD is associated with treatment outcome, and whether decreases in accommodation are associated with improved outcome. The sample consisted of 49 youths (6-18 years of age), who participated in 14 sessions of family-based cognitive-behavioral therapy for OCD, and their parents. Participants completed measures at pretreatment and posttreatment. Results indicate that family accommodation was prevalent among families of pediatric patients with OCD and that such accommodation was associated with symptom severity at pretreatment. In addition, decreases in family accommodation during treatment predicted treatment outcome, even when controlling for pretreatment OCD severity-impairment. Results suggest that the level of accommodation provided by the family may indicate an important obstacle to, or predictor of, treatment outcome in pediatric OCD. Directions for future research are discussed. (Contains 3 footnotes and 5 tables.)