A total of 6889 cadaver kidney grafts carried out in the French transplant network from 1 January 1989 to 31 December 1992 were analyzed using single and multifactorial methods in order to evaluate the impact on graft survival of matching for sex and age between donors and recipients. The mean graft survival rate was 75% at 3 yr with donors between 10 and 50 yr of age compared to 65% for donors under 10 yr of age and 67% at 3 yr for donors over 50 yr of age (p < 0.000001). For child recipients there were no significant differences in graft survival whatever the difference in age with the donor (+/- 10 yr). For young adults (17-49 yr of age) the prognosis at 3 yr was the same (75%) whether the donor was in the same age category or older than the recipient. For older adults (> 50 yr of age) a poorer prognosis was obtained when the donor was 10 yr or more older than the recipient (61% at 1 yr, p = 10(-4)). The grafts performed with male donors had a better prognosis (76% at 3 yr) than those using female donors (71% at 3 yr, p < 0.0002). The poorest results were obtained with female donors when the recipient was male (70% at 3 yr). The results of the multivariate analysis of seven parameters involved in graft survival show that the main parameters significantly controlling graft survival are preimmunization before the graft (p = 10(-6)), HLA-DR incompatibility (p = 0.004), retransplantation (p = 0.008), donor sex (p = 0.003), and matching for age between donor and recipient (p = 0.1). These results suggest that age and sex should be considered as criteria in the choice of donors and recipients in organ allocation.