Although both perfectionism and responsibility have been associated with OCD at a theoretical level, responsibility has been the focus of a number of recent articles. This study was conducted in order to empirically test the relative importance of perfectionism and responsibility in Obsessive-Compulsive symptoms. Perfectionism and two measures of responsibility showed moderate correlations with Obsessive-Compulsive symptoms. A hierarchical regression analysis revealed that although responsibility accounted for more variance, perfectionism was still a significant predictor of Obsessive-Compulsive symptoms, once responsibility had been partialled out. These results suggest that although responsibility is related to OC symptoms, perfectionism is also independently associated. While responsibility has received much attention lately from OCD theorists and clinicians, perfectionism may also play a significant if underestimated role in some OC patients. The results are discussed in terms of their implications for current cognitive models and treatment procedures that give responsibility a central role in OCD. A new definition of perfectionism is also proposed.