Eighteen participants with obsessive-compulsive disorder received 3 weeks of intensive treatment by exposure and response prevention, which were followed by either a relapse prevention (RP) program or associative therapy (AT; an attention-control program). Independent evaluators conducted assessments of obsessive-compulsive symptoms, anxiety, and depression, before and after intensive behavior therapy, after the week of intensive RP or AT and at a 6-month follow-up. Results indicated that the RP program was effective in preventing relapse: Both treatment groups improved immediately after the intensive treatment, but the RP group remained improved at follow-up, whereas the AT group showed some return of symptoms.