Abstract: The purpose of this study was to use an alternative, dimensionally based approach to understanding the reasons for comorbidity between eating disorders and obsessive-compulsive disorder. Participants from a representative community sample (N=407; 47% female) completed self-report measures of eating pathology, obsessive-compulsive symptoms, perfectionism, and neuroticism. Hierarchical multiple regression indicated that neuroticism and perfectionism completely mediated associations between most obsessive-compulsive and eating disorder symptoms. However, body dissatisfaction shared unique associations with checking, cleaning, and obsessive rituals that could not be explained by these personality traits. Results suggest that shared personality traits play a key role in the comorbidity between eating disorders characterized by binge eating and dietary restraint and obsessive-compulsive disorder. Future studies are needed to examine whether similar underlying neurocognitive processes that give rise to compulsive checking, cleaning, and obsessive rituals may also contribute to the development and maintenance of body checking in individuals diagnosed with eating disorders.