Personality characteristics of 150 morbidly obese patients (100 pounds or more over ideal weight) were investigated. The patients were given the Minnesota Multiphasic Personality Inventory (MMPI) and a new, self‐report personality disorder inventory. The study attempted to determine whether particular personality variables could predict success or failure at weight loss six months post‐surgery. Multivariate analyses of variance revealed no significant differences on any of the personality variables when the patients were divided into “good,” “fair,” and “poor” success categories. Rank order MMPI scale profiles and personality disorder profiles are presented and implications discussed.