We examined the effect of rehabilitation on the prognosis of aged patients with a first episode of acute myocardial infarction. The mean age of patients was 77 years old. We divided them into two groups, one group consisted of 53 patients for whom a rehabilitation program was available, another group consisted of 84 patients for whom a rehabilitation program was not available. Of the patients with rehabilitation available, there were 20 who were unable to receive rehabilitation, 15 who were able to participate in only light rehabilitation, 27 who were able to walk and 22 who finished rehabilitation. During 3.5 years of follow-up after initial myocardial infarction, the rates of cardiac death were 51% in the group without rehabilitation and 41% in the group with rehabilitation. For 26 patients who died of cardiac events and who had received rehabilitation, there was a positive correlation (r = 0.53) between the level of rehabilitation reached and the survival in years. The incidence of angina pectoris after myocardial infarction was more frequent in the group with rehabilitation. However the exercise activity level was higher and the prognosis was better in the group with rehabilitation, although statistical significance was not found.