OBJECTIVE: To assess the impact of insurance status on access to kidney transplantation among California dialysis patients. STUDY SETTING: California Medicare and Medicaid dialysis populations. STUDY DESIGN: All California ESRD dialysis patients under age 65 eligible for Medicare or Medicaid in 1991 (n = 9,102) took part in this cohort analytic study. DATA COLLECTION: Medicare and California Medicaid Program data were matched to the Organ Procurement and Transplantation Network Kidney Wait List files. PRINCIPAL FINDINGS: Only 31.4 percent of California Medicaid dialysis patients were placed on the kidney transplant waiting list compared to 38.8 percent and 45.0 percent of dually eligible Medicate/Medicaid and Medicare patients, respectively. Compared to the Medicaid population, Medicare enrollees were more likely to be placed on the kidney transplant waiting list (adjusted Relative Risk [RR] = 2.10, Confidence Interval [CI] 1.68, 2.62) as were dually eligible patients (RR = 1.54, CI 1.24, 1.91). Once on the waiting list, however, Medicare enrollment did not influence the adjusted median waiting time to acquire a first cadaveric transplant (p > .05). CONCLUSIONS: California dialysis patients excluded from Medicare coverage, who are disproportionately minority, female, and poor, are much less likely to enter the U.S. transplant system. We hypothesize that patient concerns with potential subsequent loss of insurance coverage as well as cultural and educational barriers are possible explanatory factors. Once in the system, however, insurance status does not influence receipt of a cadaveric renal transplant.