Psychophysiologic response patterns of 47 male duodenal-ulcer patients, 50 male hypertensive patients, and a control group of 65 men were compared by recording skin resistance level and responses, finger pulse volume, and surface integrated electromyograms during a series of verbal, acoustic, and color stimuli. Personality characteristics were examined on the basis of the Eysenck Personality Inventory, the Lüscher Test, Juhász' Neurosis Scoring Scale, and the Achievement Anxiety Scale of Alpert and Haber. Using stepwise discriminant analysis of these psychophysiologic data for the control and the hypertensive groups and the control and duodenal ulcer groups, errorless postdiction of group membership was obtained, which indicates that the autonomic parameters and psychologic traits selected as characteristics show relationships that are relevant from the diagnostic viewpoint in the groups of patients. The method could be developed into a screening test procedure for use in the early detection of persons potentially at risk.