What is the long-term outcome of patients with obsessive-compulsive disorder (OCD) who are treated with exposure and response (ritual) prevention (EX/RP) alone, serotonergic medications alone, or their combination? How is the long-term outcome of these patients affected by the discontinuation? Follow-up assessments were conducted with 62 patients treated for OCD an average of 17 months posttreatment (range: 6-43 months). Patients received one of three treatments: serotonergic medications (fluvoxamine or clomipramine), intensive behavior therapy involving EX/RP, or intensive EX/RP with concurrent antidepressant medication. At follow-up, no differences in OCD symptom severity were found among the three treatment groups. However, when current medication use was taken into consideration, differences among the three treatment groups emerged. Among patients who were medication-free at the time of follow-up assessment (n=37), those in the EX/RP-alone and EX/RP-with-medication groups had lower symptom severity ratings than those in the medication-only group on 4 out of 6 measures. There were no differences in OCD severity ratings among patients taking medications at follow-up (n=25). Although these findings are interpreted with caution due to the uncontrolled nature of the study, results suggested that long-term outcome may be superior following EX/RP than following serotonergic medications, after discontinuation. For patients who remain on medications, the treatment produced benefits equivalent to EX/RP.