During 1979 to 1987, we collected 84 consecutive cases of juvenile sudden death which occurred in the Veneto Region, northeast Italy. Death was attributed to cardiovascular disease in 79 cases. Nineteen of these (24%), consisting of 17 males and two females, from 18 to 35 years of age, had 70% or greater atherosclerotic coronary stenosis, in the absence of other cardiac pathology and previous clinical evidence of angina pectoris or myocardial infarction. In 13 cases (68%), sudden death was the first manifestation of coronary artery disease; the remaining six patients had experienced atypical, non-diagnostic prodromal symptoms. At the moment of death, 16 patients were engaged in sedentary activity. Pathological examination disclosed that in 15 cases (79%), only one major vessel was stenosed, and in 12 cases it was the proximal descending coronary artery: the other four patients had three-vessel disease. Histologic study revealed uncomplicated, obstructive fibromatous plaques in 16 cases, and a preserved tunica media in all cases. Plaque fissuring with superimposed mural or occlusive thrombosis was present in only three cases. Overt myocardial infarction was not observed. Our findings indicate that coronary atherosclerosis is an important cause of sudden death in young persons. In this series, coronary disease was 'silent', and sudden death was its first clinical manifestation. The occurrence of death at rest, in the absence of an acute coronary lesion, with preservation of the coronary tunica media suggests that fatal outcome might be due to coronary vasomotor tone abnormalities culminating in ischaemia-induced cardiac arrest.