The prevalence, nature, associations and outcome of psychiatric morbidity among four hundred and fifty severe general medical admissions are described. Affective disorder was diagnosed in 13 percent of men and 17 percent of women. It was associated with a history of previous psychiatric disorder and current social problems. Persistent affective disorder after discharge was associated with continuing medical and social problems. Alcohol problems were common in men, especially in those with social problems, and often went unrecognized by medical staff. Cognitive impairment was confined to the elderly and was associated with longer hospital stay and high mortality. Patients with emotional and cognitive disorder make considerable demands on medical, social and psychiatric services during and following admission. The implications for improved recognition and management of psychiatric morbidity in general medical patients are discussed.