Meaningful information was available on 26 patients who died suddenly in a 44,000 industrial population. The data, past illnesses, prodromal symptoms, and psychosocial information were obtained from the plant medical records, the private physicians, and mainly from direct interviews with the surviving next-of-kin, usually the wife. The data suggest that the majority of these patients, all men, had been depressed for a week up to several months. The sudden death then occurred in a setting of acute arousal engendered by increased work and activity or circumstances precipitating reactions of anxiety or anger. The findings suggest that the combination of depressive and arousal psychological states or abrupt transition from one such state to another may produce disharmonious responses in the hormonal and autonomic nervous systems, as well as central nervous system mediated behavior, which are conducive to the sudden death.