Patients with eating disorder have relatively high rates of comorbid personality disorder diagnoses, including both anxiety-based personality disorders (obsessive-compulsive and avoidant) and borderline personality disorder. However, there is preliminary evidence that the core cognitions underlying personality pathology in the eating disorders are those related specifically to anxiety. This article builds on that evidence, replicating and extending the findings with a large sample of patients with eating disorder (N = 374). There were no differences in personality disorder cognitions between eating disorder diagnoses. This study also examines the possibility that there are clusters of patients, differentiated by patterns of personality disorder cognition. Affect-related personality disorder cognitions were key to understanding the role of personality pathology in the eating disorders. It is suggested that those cognitions should be considered when planning psychological treatments.