We report the 1-year results with a triple immunosuppressive regimen in pediatric recipients of a first kidney transplant, in order to evaluate its safety and efficacy in the prevention of acute rejection and in the reduction of steroid side effects. The immunosuppression is as follows: (i) basiliximab (20 mg if body weight >30 kg; 10 mg if < 30 kg) is given pretransplant and at day 4; (ii) tacrolimus (Tac) is administered in order to obtain blood trough levels of 10-20 and 5-10 ng/ml during and after the first 2 months post-transplant, respectively; (iii) steroids are tapered during the first 6 months and then replaced by mycophenolate mofetil (depending on previous rejection episodes, infection status and the result of a routine biopsy) at a dosage of 4-600 mg/m(2) body surface area. Fifty-three children (median age 13 years, range 2-20) have entered this protocol. One-year patient and kidney survival are 100% and 94% respectively. During the first year a total of nine rejections in seven patients (13% of the cohort study) occurred, all but one responsive to steroids. Renal function was satisfactory throughout the first year (mean CrCl was 63.8 +/- 18 and 60.9 +/- 15.5 ml/min/1.73 m(2) at 6 and 12 months respectively). Subclinical signs of rejection were absent in more than 80% of biopsies (grade I Banff) at 6 months (n = 47); at the 12th month biopsy (n = 42) score I was stable in 20 patients (16 after stopping steroids) and had worsened in eight biopsies (six after stopping steroids). Major complications were insulin-dependent diabetes in three (5.6%) children with the need of insulin for a mean of 3 months; transient hyperglycemia (11 patients), treated with a dietary regimen, symptomatic viral infections (in 11 patients: two parvovirus B19, three cytomegalovirus and two Epstein-Barr virus systemic infections, three interstitial pneumonia, two BK nephritis). Tac doses more than 0.3-0.4 mg/kg/day are at significantly higher risk of viral infection. In conclusion, this immunosuppressive regimen is associated with a low percentage of clinical (13%) and subclinical rejections, but with a relatively high number of infections, prevented by a reduction in Tac doses (<0.3 mg/kg/day) during the first 2 months after transplantation. The assessment of steroid withdrawal needs a longer follow-up.