The availability of renal transplantation to individuals with end-stage renal disease (ESRD) is an issue of considerable concern. The role of age, race, sex, socioeconomic status, illness severity, and comorbidity in determining access to this therapy remains unclear. We examined the influence of these factors on transplant candidacy in 8,315 patients receiving dialysis treatment for ESRD in North Carolina, South Carolina, and Georgia. We found important race-sex differences in the likelihood of being identified as a transplant candidate. These differences persisted after adjustment for other patient characteristics, including illness severity and certain comorbid conditions. Characteristics found to be positively associated with candidacy included age less than 30 years (P less than 0.00001), living with a spouse and children (P = 0.004), and employment status (P = 0.006). Characteristics and comorbid conditions that were negatively associated with candidacy included 8 years or less of formal education (P = 0.001), cancer (P = 0.0006), visual impairment (P = 0.006), congestive heart failure (P = 0.008), and peripheral vascular disease (P = 0.01). Compared with white males, after adjustment for these factors, the likelihood (95% confidence interval) of being identified as a transplant candidate was: white females, 0.88 (0.65 to 1.18); black males, 0.77 (0.59 to 0.99); and black females, 0.66 (0.51 to 0.87). We conclude that although socioeconomic and medical factors are strongly associated with transplant candidacy, these associations do not adequately explain the observed race-sex differences in transplant candidacy status.