From June 1960, to Jan. 1976, 157 patients 65 yr or older had elective operations with cardiopulmonary bypass. Ninety-three patients had 1 or 2 valves replaced, 47 had coronary artery surgery, and 17 had both. The operative mortality rate was 22.6% (21 of 93), 19.1% (9 of 47), and 5.8% (1 of 17), respectively. The over-all mortality rate was 19.7% (31 of 157). The mortality rate in patients of 65-69 yr of age was 20% (22 of 110) and 19% (9 of 47) in patients 70 yr or more. Ninety-four of these operations were performed within the last 3 yr, with a reduction in patients'' mortality rate to 9.6% (9 of 94). A retrospective study revealed a significant correlation between operative mortality rate and preoperative heart size. No correlation could be found between operative mortality rate and diabetes, smoking history, or hyperlipidemia. The major causes of death were myocardial infarction (68%, 21 of 31), pulmonary complications (35%, 11 of 31), infections (29%, 9 of 31) and renal failure (29%, 9 of 31) or combinations thereof. The patients who died had 2.5 times the number of complications of the survivors. Ninety percent of the patients in the past 3 yr survived their operation. Elective cardiac operations can be performed with an acceptable mortality rate in patients over the age of 65 yr.