Six hundred thirty-eight cadaveric kidney transplant patients between 1983 and 2001 were treated with cyclosporine (CsA) for 87 +/- 58 months. Among 571 patients with follow-up greater than 12 months, the 15-year renal function was investigated to assess the probability of a >30% increase in serum creatinine (sCr) above the month-6 value (baseline) and the impact on graft survival. At 15 years, patient and graft survival rates were 82.7% and 56.1%, respectively, with a 19.5-year half-life (censored for deaths). The main causes of graft loss were chronic rejection (33.0%) and patient death (24%). Cardiovascular disease and neoplasms were the main causes of death. Renal function remained stable in 266 patients (46.6%) with excellent sCr values observed even after a 15-year treatment period. An increased sCr was observed in 305 patients (53.4%) with a 15-year probability of 74%. In 178 patients (59.3%) it was self-limited; their grafts are still functioning well. One hundred three patients (32.8%) lost their graft which was more likely when the sCr had increased >45%. Twenty-four patients (7.9%) died with a functioning graft. Multivariate analysis showed the progression of graft deterioration to be related to proteinuria (P<.0001), a late acute rejection episode (P<.002), or the extent of sCr increase (P<.008). In conclusion, the long-term use of CsA has allowed us to achieve excellent long-term patient and transplant survival rates. Our data indicate a high 15-year probability of an increased sCr, but the rate of progression is slow.