This article synthesizes the evidence on the cost-effectiveness of renal replacement therapy and discusses the findings in light of the frequent practice of using the cost-effectiveness of hemodialysis as a benchmark of societal willingness to pay. The authors conducted a meta-analytic review of the medical and economic literature for economic evaluations of hemodialysis, peritoneal dialysis, and kidney transplantation. Cost-effectiveness ratios were translated into 2000 U.S. dollars per life-year (LY) saved. Thirteen studies published between 1968 and 1998 provided such information. The cost effectiveness of center hemodialysis remained within a narrow range of $55,000 to $80,000/LY in most studies despite considerable variation in methodology and imputed costs. The cost-effectiveness of home hemodialysis was found to be between $33,000 and $50,000/LY. Kidney transplantation, however, has become more cost-effective over time, approaching $10,000/LY. Estimates of the cost per life-year gained from hemodialysis have been remarkably stable over the past 3 decades, after adjusting for price levels. Uses of the cost-effectiveness ratio of $55,000/LY for center hemodialysis as a lower boundary of society's willingness to pay for an additional life-year can be supported under certain assumptions.