Individuals vulnerable to obsessive-compulsive disorder (OCD) are hypothesized to have ambivalence about their self-worth, morality and lovability [Guidano, V., & Liotti, G. (1983). Cognitive processes and emotional disorders. New York: Guildford Press]. The purpose of this study was to examine whether self-ambivalence was associated with OCD phenomena and beliefs relevant to OCD. It also examined whether patients with OCD had higher levels of self-ambivalence compared to non-clinical controls and patients with other anxiety disorders. Participants were 73 OCD patients, 50 patients with another anxiety disorder, 225 non-clinical undergraduate students and 43 non-clinical community controls. They completed measures of self-ambivalence, OCD phenomena, OCD-relevant beliefs, depression, anxiety and self-esteem. Self-ambivalence was significantly associated with OCD phenomena and OCD-relevant beliefs, after controlling for self-esteem, depression and anxiety. Further, OCD participants were significantly more ambivalent than the non-clinical groups, but did not differ from anxious controls. It was argued that these results provide a basis for extending the cognitive-behavioural model of OCD to include ambivalent self-perceptions as a component of the cognitive mechanisms relevant to the disorder.