High-flux dialysis is a new method for providing routine-maintenance hemodialysis to patients with endstage renal disease. It promises to shorten the duration of the dialysis session, but poses potential clinical risks to patients and financial risks to dialysis centers because of the high unit cost of purchasing new dialysis equipment. We retrospectively evaluated the cost-effectiveness of high-flux dialysis compared to conventional dialysis in a hospital-based center. The center provided only conventional dialysis until March 1989, when it initiated high-flux dialysis. The estimated annual costs of treatment were US $31,249 (high-flux) and $32,562 (conventional). The rate of hospital admissions was almost identical in both groups (conventional, 1.29 admissions per year; high-flux, 1.24 admissions per year; p = 0.23). Predicted prolongation of life expectancy with high-flux dialysis was significantly higher after statistical adjustment for observable patient characteristics (1.8 to 4.5 years; p <0.01). The cost-effectiveness ratio was $28,188 per life-year saved for high-flux compared to conventional dialysis. These findings suggest that the added capital expense of purchasing high-flux equipment can be justified from the perspective of its societal cost-effectiveness.