This national study compares waitlisting and transplantation rates by gender, race, and diabetes and evaluates physiologic factors (panel-reactive antibodies [PRA], blood type, HLA matchability) and related practices (early and multiple waitlisting) as explanatory factors. This longitudinal study of the time to transplant waitlisting among 228,552 incident end-stage renal disease (ESRD) dialysis patients and to cadaveric transplantation among 46,164 waitlist dialysis patients (n = 23,275 first cadaveric transplants) used US data for 1991 to 1997. Relative rates of waitlisting (RRWL) after ESRD onset and of cadaveric transplantation (RRTx) after waitlist (Cox proportional hazards models) were adjusted for age, race, sex, ESRD cause, region, and incidence/waitlist year. We found that women have an RRWL = 0.84 (P < 0.0001) and RRTx = 0.86 (P < 0. 0001). PRA levels can explain the difference in the transplantation rate, because accounting for PRA gives an adjusted RRTx = 0.98 (NS) for women. For blacks versus whites, the RRWL = 0.59 (P < 0.0001) and RRTx = 0.55 (P < 0.0001). However, the transplantation rate can only partly be explained by ABO types, rare HLA types, and early and multiple waitlisting (adjusted RRTx = 0.67 [P < 0.0001]). For diabetes versus glomerulonephritis, the RRWL = 0.52 (P < 0.0001) and RRTx = 0.98 (NS). Older patients (40 to 59 years of age) are less likely to be waitlisted and to receive a transplant after waitlisting (RRWL = 0.57 [P < 0.0001], RRTx = 0.88 [P < 0.0001]) versus younger patients (ages 18 to 39 years). These results indicate substantial differences by age, sex, race, and diabetes in rates of waitlisting for transplantation and by age and race for transplantation after waitlisting. These differences by race were not explained by referral practices or the physiologic factors studied here.