The present study examined whether the comorbidity of obsessive-compulsive personality disorder (OCPD) and obsessive-compulsive disorder (OCD) constitute a specific subtype of OCD. The study sample consisted of 146 consecutive outpatients with a DSM-IV diagnosis of OCD. Diagnoses were established using MINI, IPDE, YBOCS and YBOCS-SC. OCD patients with comorbid OCPD were compared with OCD patients without OCPD on various sociodemographic and clinical variables. Almost one third of the OCD subjects met criteria for comorbid OCPD. OCD+OCPD patients had a significantly earlier age at onset of initial OC symptoms, earlier age at onset of OCD and more obsessions and compulsions than pure obsessions compared to the patients with OCDOCPD. OCD+OCPD patients also had a higher rate of comorbidity with avoidant personality disorder and showed more impairment in global functioning. There were not differences between the two sub-groups on severity of OCD symptoms and also on type of OCD onset. Our results indicate that the comorbidity of OCD with OCPD is associated with a number of specific clinical characteristics of OCD. These findings in conjunction with of current clinical, family and genetic studies provide some initial evidence that OCD comorbid with OCPD constitute a specific subtype of OCD.