Lower rates of transplantation among minority groups are a nationally recognized phenomenon. Native Americans (NA) nationally have nearly four times the risk of end-stage renal disease (ESRD) as compared with white (W) Americans and are significantly overrepresented in the Network 15 ESRD population. To understand more about NA and W transplant rates, we looked at all reported Arizona (AZ) and New Mexico (NM) resident cases from the Network No. 15 data base. Age of onset, sex, primary diagnosis, payment source, transplant donor source, and other factors were examined. NA experienced a slightly earlier onset of ESRD than W, and diabetes mellitus was the primary ESRD diagnosis for 63-73% of NA and for 34-39% of W. Because age distribution and frequency of diabetes mellitus of the NA ESRD population differ from those of W in the Network, age-specific and diagnosis-specific transplant rates were examined. Age-adjusted transplant rates per 100 ESRD patients for AZ were 16.4 (NA) and 21.0 (W) and for NM 14.2 (NA) and 22.4 (W). Diagnosis-specific age-adjusted transplant rates for patients with the primary diagnoses of diabetes mellitus and glomerulonephritis, the two most common causes of ESRD among NA, showed a large difference between W and NA rates. Age-adjusted rates for diabetes were: AZ 8.4% (NA) and 14.5% (W); NM 9.8% (NA) and 15.9% (W). Age-adjusted rates for patients with glomerulonephritis were: AZ 23.7% (NA) and 28.0% (W); NM 22.3% (NA) and 33.0% (W). In all comparisons and in both the W and NA ESRD populations, women were transplanted at lower rates than men. NA experienced a greater delay from onset of treated ESRD to transplant than W. Payment source and transplant donor source did not appear to be significantly different between NA and W. The lower transplant rates in NA versus W in Network No. 15 cannot be explained by age- or diagnosis-specific factors.