The autopsy reports of the Pathological Institute Erfurt of the period from 1.1.1951 until 31.12.1969 were scored for cases of myocardial infarction and coronary thrombosis. Among 2,393 morphologically analysed myocardial infarctions 454 coronary thromboses (18.97 per cent) were found. Males were significantly more affected than females. Fresh infarcts showed significantly more thromboses than callous infarcts. We found fresh and occluding vessel thromboses more frequently in fresh infarctions. The analysis of age distribution yielded an increase of the rate of thrombosis in cases with myocardial infarction. On the other hand, the frequency of infarctions in cases with a coronary thrombosis was decreasing. It is suggested that the risk for infarctions is larger in younger people with coronary thrombosis than in older ones. No infarctions were detected in 165 cases of thrombosis. Preferably this group includes those cases in which the patients deceased within 6 to 8 hours and, therefore, the infarction was not morphologically detectable.