An epidemiological study of sudden and unexpected death was conducted in Baltimore city during 1964 and 1965. Of the 322 nontraumatic deaths reviewed, 101 (31.4%) were sudden and unexpected. Sudden, unexpected deaths were more common in Negroes and men. Alcoholism and fatty liver was the leading cause of sudden, unexpected death, accounting for 27.7% of the sudden deaths, while 21.8% were due to arteriosclerotic heart disease.