Attention is called to the development of coronary heart disease in two patients several years after they received mediastinal irradiation for Hodgkin's disease. One patient, a 33 year old man, died suddenly eight years after irradiation; necropsy disclosed marked narrowing of all three major coronary arteries. In addition to severe intima fibrous thickening, there also was considerable adventitial scarring of the coronary arteries. This type of coronary sclerosis is different from that seen in the usual patient with coronary heart disease. The second patient, a 42 year old man, had an acute myocardial infarction on two occasions, the first six years after mediastinal irradiation. Observations in previously described patients with coronary heart disease almost surely induced by therapeutic irradiation for Hodgkin's disease are reviewed.