The study concerned an investigation of the relationship between selected personality dimensions and several measures of overt behaviour among hospitalized TB patients. A structured Q-sort was constructed to measure the selected dimensions of personality. It was administered to all patients who were 45 years of age and less and who were admitted to the Madison Veterans Administration Hospital, Wisconsin, USA. Data were obtained at an early point in each patient's hospitalization. Assessment of patient behaviour was accomplished by use of the Ward Behavior Rating Scale. The head nurse of each ward rated each subject of her ward, using this scale, approximately three months after the patient's admission to the hospital. It appears that the manifest behaviour of hospitalized tuberculous patients, both in its voluntary aspects (such as ward behaviour) and in its involuntary aspects (such as physiologic response to medical treatment), is to a significant extent a function of personality factors. Some of these personality variables, assessed early in hospitalization, are related predictably to subsequent behaviour patterns. The general implication of the findings supports the view that comprehensive management of TB must take the total person and not only his physical disease as the object of treatment.