This chapter summarizes analyses of 66,843 kidney-only transplants reported to the OPTN/UNOS Renal Transplant Registry between January 1999-December 2003. The 5- and projected 10-year graft survival rates for 28,260 recipients of living donor (LD) kidneys were 80.5% and 67.0%, respectively, based on a computed halflife of 17.8 years for those grafts that survived one year. Comparable results for 33,118 recipients of standard criteria deceased donor (SCD) and 5,943 recipients of expanded criteria deceased donor (ECD) kidneys were 68.8% and 50.9%, and 51.8% and 32.9%, respectively. The half-lives for SCD and ECD were 10.8 and 6.8 years, respectively. ECD kidneys (from donors aged 60+ or 51-59 with other risk factors) were preferentially transplanted to older patients (median age 58) even though there was no formal requirement to allocate these kidneys to older patients. The oldest recipients of deceased donor (DD) kidneys, 991 aged 71-75 and 254 over age 75 had 5-year graft survival rates of 48.9% and 40.7%, respectively and 40% of graft losses in these groups were due to death with a functioning graft. Among 469 LD kidney recipients over age 70, graft survival rates were 70% or higher with 40% of grafts lost due death with function. About 13% of DD and 5% of LD kidneys were transplanted to broadly sensitized patients during this period. One-fourth and one-fifth of broadly sensitized patients who were transplanted received an HLA-matched DD or LD kidney, respectively. Overall, the proportion of transplants to unsensitized patients has increased in recent years to more than 50% of DD and nearly 70% of LD kidneys. There was no apparent correlation between the sensitivity of crossmatch tests and graft survival of first or repeat DD transplants; however, use of the more sensitive flow cytometry and AHG enhanced crossmatches significantly reduced the incidence of early rejections. Mean cold ischemia times have declined by about 7 hours between 1991- 2003, but the reduction in average cold time has not produced any notable reduction in the incidence of delayed graft function for recipients of SCD or ECD kidneys. Histocompatibility laboratories that waited for donor spleen or lymph node cells to perform final crossmatches added an average of 3 hours of cold ischemia for the kidneys they tested compared with laboratories that performed the tests with peripheral blood lymphocytes. There was no net increase in delayed graft function (DGF) with SCD kidneys tested at labs using spleen or nodes but the incidence of DGF among ECD kidneys was 25% when the lab used PBLs and 35% when the lab used spleen or nodes.