There is little information on the long-term outcome of patients initially assigned to cyclosporine (CsA) monotherapy and requiring the addition of steroid therapy during follow-up. The aim of this report is to describe our experience with 143 first renal transplant recipients (120 cadaver transplants, 23 living donor transplants) randomized to receive CsA monotherapy as a treatment arm of three consecutive controlled clinical trials. Median follow-up was 86 months. Thirty-four percent of the patients remained on the original CsA monotherapy, whereas the remaining 66% required the addition of steroid therapy. Cumulative patient and graft survivals at 11 years were 0.89 (95% confidence interval [CI], 0.83 to 0.95) and 0.62 (95% CI, 0.52 to 0.72), respectively. The 11-year graft survival for converted patients was 0.53 (95% CI, 0.39 to 0.67). Cumulative graft half-life was 19.9 +/- 3.47 (SE) years. According to the Cox model, variables at transplantation that correlated with a lower 11-year graft survival were yearly increases in age (relative risk [RR], 1. 04; P = 0.039), monthly increases in hemodialysis duration (RR, 1.01; P = 0.029), no blood transfusion before transplantation (RR, 1.99; P = 0.043), CsA administration in a double daily dose (RR, 2.35; P = 0.008), and a cadaver donor transplant (RR, 4.76; P = 0.039). Multivariate analysis of time-dependent variables showed that delayed graft function recovery (RR, 2.20; P = 0.019) and the need to add steroid and/or azathioprine therapy (RR, 5.28; P = 0.000) were also correlated with a lower graft survival. Patients who added steroid therapy developed infections (P < 0.001), cataracts (P < 0.001), cardiovascular complications (P = 0.004), and arterial hypertension (P = 0.024) more frequently than patients remaining on CsA monotherapy. Patients administered CsA in a single daily dose received significantly less CsA over the years (P = 0.0042) than patients administered CsA in two divided doses. They also showed a trend toward greater creatinine clearance levels, although not statistically significant. In conclusion, this analysis showed that in patients assigned to CsA therapy alone, good long-term patient and graft survival probabilities can be obtained. In approximately one third of the patients, the use of steroids could be avoided for up to 11 years, and these patients had a better long-term outcome than those who required the addition of steroid therapy. Finally, in patients administered CsA in a single daily dose, the possibility of reducing CsA dosage probably led to better intrarenal hemodynamics with improving creatinine clearances.