OBJECTIVE: This study describes 1-year treatment outcomes from a large sample of cognitive-behavioral therapy (CBT) responders, investigates age as a possible moderator of these treatment outcomes, and evaluates clinical relapse at the 1-year follow-up. METHOD: This study is the planned follow-up to the Nordic Long-term OCD [obsessive-compulsive disorder] Treatment Study (NordLOTS), which included 177 children and adolescents who were rated as treatment responders following CBT for OCD. Participants were assessed with the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) at 6- and 12-month follow-up. Treatment response and remission were defined as CY-BOCS total scores ≤15 and ≤10, respectively. Linear mixed-effects models were used to analyze all outcomes. RESULTS: At 1 year, a total of 155 children and adolescents (87.6%) were available for follow-up assessment, with 142 of these (91.6%) rated below a total score of ≤15 on the CY-BOCS. At 1-year follow-up, 121 (78.1%) were in remission. On average, CY-BOCS total scores dropped by 1.72 points during the first year after terminating treatment (p = .001). A total of 28 participants (15.8%) relapsed (CY-BOCS ≥ 16) at either the 6- or 12-month assessment; only 2 patients required additional CBT. CONCLUSION: Results suggest that manualized CBT in a community setting for pediatric OCD has durable effects for those who respond to an initial course of treatment; children and adolescents who respond to such treatment can be expected to maintain their treatment gains for at least 1 year following acute care. Clinical trial registration information- Nordic Long-term Obsessive-Compulsive Disorder (OCD) Treatment Study; www.controlled-trials.com; ISRCTN66385119.