Forty patients with chronic duodenal ulcer were studied to determine whether some particular personality and psychological factors are associated with this disease. To this purpose the Cattell's PF 16 personality Test was utilized. Duodenal ulcer population presented a typical personality profile characterized by: high anxiety, dependence and introversion. Some biological parameters, suggested as predictors of slow healing and/or relapse of ulcer, were studied: patients with maximal acid output greater than 60 mEq/h and /or total serum pepsinogen greater than 109 micrograms tyr/ml/24 hrs and/or serum pepsinogen group I greater than 99 ng/ml showed an anxiety level significantly higher than that of patients with values less than the reported thresholds. These results suggest a contributory role by psychological factors in duodenal ulcer disease. The association of anxiolitic drugs to the traditional antiulcer therapy may be proposed, particularly in hypersecretors.