Very little is known about dreams in patients with obsessive compulsive disorder, especially regarding changes over the course of treatment with stimulus exposure and response prevention. By use of dream content analysis, 40 dreams of 9 obsessive compulsive (OC) inpatients were compared with 84 dreams of 10 matched OC outpatients and 63 dreams of 11 healthy control participants. Dream protocols of inpatients were collected at the beginning of treatment and after the first exposure exercises. Controls filled in dream protocols in respective intervals. Before treatment, dreams of patients showed significantly less positive contents than dreams of healthy controls. Under treatment with exposure, a significant reduction of OC themes was observed. The findings support the continuity hypothesis of dreaming by showing a link between day-time symptoms and OC symptoms in dreams. Contrary to expectations, however, exposure treatment does not intensify dreams.