The heart was found to be involved in 3 of 15 cases of Hodgkin's disease. In one patient, a 46-year-old man, the myocardium showed a striking degree of fibrosis, with nodules of cells exhibiting extreme pleomorphism and a tumor mass protruding into the cavity of the right atrium. In the second patient, a 68-year-old woman, an infiltrate of lymphocytes, macrophages, and Reed-Sternberg cells was found in both myocardium and epicardium. In the third patient, a 50-year-old man, two nodules on the epicardial surface revealed massive infiltration of the subepicardial tissue with large pleomorphic cells, multinucleated giant cells, typical Reed-Sternberg cells, and nests of lymphocytes. In each case the history contained some evidence of cardiac disturbance. Unexplained arrhythmias and decompensation refractory to the usual treatment are two common manifestations of myocardial metastases.