The influence of donor age on outcome was studied in the recipients of 12,131 cadaveric renal allografts, 3026 heart allografts, and 2913 liver allografts with followup information in the UNOS data base for transplants performed between 10/1/87 and 12/31/89. For recipients of kidney transplants, donors of ages 6-15 had significantly better 1-year graft survival than donors of ages 56-65, but the difference was only 7.0%. Donors of age greater than 65 actually did better than donors ages 56-65, but donors less than or equal to 5 were less satisfactory. Kidneys from older donors survived as well as kidneys from younger donors in patients with repeat transplants, diabetes, black race, age over 45, O HLA or 5 and 6 HLA matches, delayed graft function, shared kidneys and PRA greater than 50. For kidney recipients, multifactorial analysis by Cox regression showed that donor age was less important than the use of ALG, donor race, diabetes or peak PRA in ages 16-45, delayed function, repeat transplant, and HLA match. Recipients of heart transplants from donors ages 45-55 had 1-year graft survival that was 8.4% less than recipients of hearts from donors age 16-45. However, 32.7% of heart patients died during the first 12 months after listing without benefit of a transplant. Liver transplant recipients of donor ages 16-45 had 10.8% better 1-year graft survival than recipients of donors greater than 45, but a greater percentage of older donors were transplanted to high risk and older recipients. Tragically, 24.3% of patients listed for liver transplantation died within 12 months without a transplant. This analysis shows that satisfactory graft survival can be achieved using older donors and that age in itself should not be a barrier to organ donation, providing that organ function is normal and that specific disease of the organ is absent.