Body dysmorphic disorder (BDD) is currently classified as a somatoform disorder in DSM-IV, but has been long noted to have some important similarities with obsessive-compulsive disorder (OCD). In addition, BDD and OCD have been often reported to be comorbid with each other. In the present study, we compared demographic characteristics, clinical features and psychiatric comorbidity in patients with OCD, BDD or comorbid BDD-OCD (34 subjects with BDD, 79 with OCD and 24 with BDD-OCD). We also compared the pattern of body dysmorphic concerns and associated behaviors in BDD patients with or without OCD comorbidity. In our sample, BDD and OCD groups showed similar sex ratio. Both groups with BDD and BDD-OCD were significantly younger, and experienced the onset of their disorder at a significantly younger age than subjects with OCD. The two BDD groups were also less likely to be married, and more likely to be unemployed and to have achieved lower level degree, than OCD subjects even when controlling for age. The three groups were significantly different in the presence of comorbid bulimia, alcohol-related and substance-use disorders, BDD-OCD patients showing the highest rate and OCD the lowest. BDD-OCD reported more comorbid bipolar II disorder and social phobia than in the other two groups, while generalized anxiety disorder was observed more frequently in OCD patients. Patients with BDD and BDD-OCD were similar as regards the presence of repetitive BDD-related behaviors, such as mirror-checking or camouflaging. Both groups also did show a similar pattern of distribution as regards the localization of the supposed physical defects in specific areas of the body. The only significant difference concerned the localization in the face, that was more frequent in the BDD group. Our results do not contradict the proposed possible conceptualization of BDD as an OCD spectrum disorder. However, BDD does not appear to be a simple clinical variant of OCD and it seems to be also related to social phobia, mood, eating and impulse control disorders. The co-presence of BDD and OCD features appears to possibly individuate a particularly severe form of the syndrome, with a greater load of psychopathology and functional impairment and a more frequent occurrence of other comorbid mental disorders.