We sought to determine whether adults with obsessive-compulsive disorder (OCD) who respond to intensive exposure and response (ritual) prevention (EX/RP) with or without clomipramine (CMI) fare better 12 weeks after treatment discontinuation than responders receiving CMI alone. After receiving 12 weeks of treatment (EX/RP, CMI, EX/RP+CMI, or pill placebo [PBO] in a randomized clinical trial conducted at three outpatient research centers), 46 adults with OCD who responded to treatment (18 EX/RP, 11 CMI, 15 EX/RP+CMI, 2 PBO) were followed after treatment discontinuation for 12 weeks. Patients were assessed every 4 weeks with the Yale-Brown Obsessive-Compulsive Scale, the National Institutes of Health Global Obsessive-Compulsive Scale, and the Clinical Global Impressions scale by an evaluator who was blind to original treatment assignment. The primary hypothesis was that EX/RP and EX/RP+CMI responders would be less likely to relapse 12 weeks after treatment discontinuation than responders to CMI alone. Twelve weeks after treatment discontinuation, EX/RP and EX/RP+CMI responders, compared to CMI responders, had a significantly lower relapse rate (4/33 = 12% versus 5/11 = 45%) and a significantly longer time to relapse. The CMI relapse rate was lower than previously reported. Nonetheless, responders receiving intensive EX/RP with or without CMI fared significantly better 12 weeks after treatment discontinuation than responders receiving CMI alone.