BACKGROUND Traditionally, elderly donor kidneys have not been widely accepted for transplantation on the assumption of inferior performance. However, the United Network for Organ Sharing reports an increase in the number of elderly donors from less than 2% in 1982 to 24% in 1995. This trend is commensurate with the increase of older dialysis patients and an overall increase in the elderly population in the United States (1). Optimal utilization of these kidneys is essential to overcome the acute organ shortage. METHODS In this study, we transplanted 25 kidneys from elderly donors (ages 56-72 years) into young adult recipients (ages 20-50 years) (group 1) over a 4-year period. We compared the results with matched recipients of young adult donor kidneys (group 2) with regard to long-term kidney function and graft survival. A pretransplant biopsy of elderly donor kidneys was carried out and a frozen section report was obtained. Only those kidneys showing glomerulosclerosis of less than 20% were accepted for transplantation. All cadaveric kidneys were preserved in University of Wisconsin solution. RESULTS Pretransplant biopsies of elderly donor kidneys showed structural deficits, which included glomerulosclerosis in 85%, arteriolar and/or mesangial thickening in 75%, and interstitial lymphocyte infiltration in 30%. The mean serum creatinine was 2.4+/-0.74, 2.2+/-0.56, and 2.9+/-0.76 mg/100 ml in group 1 and 1.5+/-0.55, 2.3+/-2.24, and 1.7+/-0.62 in group 2 at 1, 3, and 5 years, respectively. The patient survival was 92%, 92%, and 88% in group 1, and 100%, 100%, and 100% in group 2 at 1, 3, and 5 years, respectively. The graft survival was 80%, 64%, and 56% in group 1 and 100%, 96%, and 88% in group 2 at similar time intervals. The differences in the serum creatinine and graft survival between the two groups were statistically significant (P < 0.05). CONCLUSIONS Most of the elderly donor kidneys with structural deficits transplanted into young adults provided suboptimal function and inferior long-term graft survival. To maximize the utilization and optimize the survival of elderly donor kidneys, we propose transplantation of these kidneys into age-matched recipients with similar physiological requirements as those of donors, with regard to kidney function.