Except for rarely performed psychosurgery, obsessive compulsive disorder seldom improved with reversible treatments before 1966. In that year, Victor Meyer reported successful treatment of OCD with behavior therapy, and clomipramine was first released. For the past 25 years, controlled research has demonstrated specific efficacy of exposure for obsessional anxiety and ritual or response prevention for reducing ritual time, interference, and associated distress. Over the same time span, clomipramine has been conclusively shown to be an effective treatment for obsessive compulsive disorder in double-blind controlled trials against placebo and other nonpotent serotonin uptake inhibitor antidepressants. Fluvoxamine, fluoxetine, and sertraline, all potent serotonin uptake inhibitors, have also demonstrated efficacy in obsessive compulsive disorder; fluvoxamine is the best studied of these three compounds. The combination of behavior therapy and a potent serotonin uptake inhibitor is currently the best treatment for most patients. Psychosurgery still has a part to play in the treatment of a small proportion of severely disabled and distressed obsessive compulsive patients unresponsive to other effective treatments.