Autopsy findings in 3 White men who died suddenly during or after exercise are described. Two were well conditioned marathon runners who had recently completed a 90 km ultramarathon, while the third was active in sports other than running. At autopsy all had significant coronary artery disease (CAD) involving the left anterior descending and right coronary arteries and macroscopic or histological features diagnostic of hypertrophic cardiomyopathy (HCM). Although CAD and HCM are well-established causes of sudden death in athletes, the combination is uncommon. The absence of symptoms prior to death in 2 of the subjects indicates that the possibility of antemortem diagnosis (particularly of HCM) was unlikely.