A three-phase treatment of patients with obsessive-compulsive disorder is described with 9 case-studies. In the first phase, patients received 60 mg fluoxetine during 12 weeks. In the second phase, 12 weeks of cognitive behaviour therapy (cbt) was added. In the last phase, fluoxetine was discontinued while cbt was continued. Objective of this study was to investigate whether additional cbt prevented relapse in fluoxetine treatment. Seven patients improved significant on the Yale-Brown Obsessive-Compulsive Scale during treatment, but 4 patients relapsed at follow-up after 5 months. The addition of cbt to fluoxetine treatment did not prevent relapse in this study. Several patterns of improvement across the patients are discussed.