In this study, we sought to characterize obsessive-compulsive disorder (OCD) patients with impulsive features, and to determine whether they constitute a distinct subtype of OCD. Therefore we systematically assessed impulse control disorders and other impulsive conditions categorized as obsessive-compulsive spectrum disorders (OCSDs) in 153 Japanese adult patients with OCD. Forty-five subjects (29%) had concurrent impulsive disorders, and they were differentiated from other OCD patients on a range of demographic features (e.g., younger age at onset), and clinical features (e.g., pervasive and severe psychopathology, and poor treatment outcome). However, on logistic regression, none of these variables predicted comorbid impulsivity. The findings appear to support the argument that OCD patients with impulsive features constitute a subtype of OCD. However, further research is necessary to determine whether impulsivity should be conceptualized as lying on a spectrum with compulsivity or as a dimension that is orthogonal to compulsivity.