A 67 item self-report questionnaire called the Meta-Cognitive Beliefs Questionnaire (MCBQ) was developed to assess endorsement of beliefs about the importance of control and negative consequences associated with unwanted, ego-dystonic intrusive thoughts, images and impulses. The MCBQ and a battery of questionnaires that assessed symptoms and cognitions of worry, obsessive-compulsive disorder, anxiety, and depression were administered to large samples of undergraduate students. Beliefs about control of intrusive thoughts and perceived negative consequences due to uncontrolled mental intrusions had a unique significant relationship with obsessions, and to a lesser extent, worry. These findings are consistent with current cognitive behavioral theories that suggest an important role for meta-cognitive beliefs in the pathogenesis of obsessions.