To clarify the relationship between dissociative symptoms and obsessive-compulsive disorder (OCD), 100 patients with OCD were assessed with standardized instruments measuring symptoms of OCD, dissociation, and depression. Diagnoses of personality disorders and dissociative disorders were made using structured interviews. Compared with a previous study, OCD patients had dissociation scores slightly higher than normal controls and comparable to patients with other anxiety disorders. Patients with elevated dissociation scores had more severe OCD symptoms, were more depressed, and were more likely to have a personality disorder than patients with low dissociation scores. Although dissociative symptoms were frequently reported by OCD patients, symptoms of OCD may also mimic dissociation in some patients.