Little necropsy information is available on donor hearts in place in recipients for varying periods. Necropsy studies were performed in 79 patients who had survived from 1 day to 17 years after orthotopic heart transplantation (OHT). At OHT, the 79 patients ranged in age from 3 to 70 years (mean 51), and at death, from 20 to 76 years (mean 54). The native hearts tended to be larger than the donor hearts in the 22 patients surviving ≤60 days and the donor hearts tended to be larger in the 57 patients surviving >60 days, suggesting that the donor hearts increased in weight with time. Cardiac adiposity increased with time. Grossly visible myocardial lesions were seen in 24 (30%) of the 79 cases: necrosis only in 20; fibrosis only in 2, and both in 2. One or more epicardial coronary arteries were narrowed >75% in cross-sectional area in 25 (32%), 1 of whom was in the group surviving ≤60 days. The right ventricular cavity was dilated in 73 cases (92%) and the left ventricular cavity in 39 cases. Evidence of graft rejection (lymphocytic infiltrates) was found in 50 patients (63%); in 8 (36%) of the 22 patients surviving ≤60 days, and in 42 (74%) of the 57 surviving >60 days. The lymphocytic infiltrates were largest in the subepicardial adipose tissue, next in myocardium, and least in endocardium. The quantity of the cellular infiltrates varied considerably among the patients. In conclusion, with time, the donor hearts tended to increase in weight, in the quantity of adipose tissue, in the amounts of coronary narrowing, in the frequency of ventricular cavity dilatation (particularly the right ventricle), and in the frequency of lymphocytic infiltrates (evidence of rejection).