Patients who were diagnosed as polyps or nodules of vocal cords (PN group), and two control groups were tested with Japanese version of Maudsley Personality Inventory to evaluate the personality characteristics of patients with these behavior-induced vocal cord diseases. PN group showed significantly higher E (extraversion-introversion) scores than each control group. This extraversive tendency had no relation to their age, sex, polyp or nodule, and occupation. N (neuroticism) scores were not significantly different between PN group, and each control group. L (lying) scores of PN group were significantly lower than a control group. It was suggested that extraversive personality was one of the important factors relating to the pathogenesis of vocal cord polyp and nodule.