The aim of this study was to analyze the impact of TAC on medium term (three-yr follow-up) renal function in pediatric liver transplant (OLT) recipients. Glomerular and tubular indices were retrospectively analyzed in 24 consecutive OLT pediatric recipients on TAC. CrCl increased significantly each month post-OLT (p = 0.003), with a trend toward significance between pre-OLT and 36 months (p = 0.17). There was no correlation between CrCl and TAC troughs (p = 0.783). Sixteen percent of patients had CrCl <60 mL/min/1.73 m(2) pre-OLT vs. none at 36 months post-OLT. TRP values were normal throughout the study. UPr/Cr decreased insignificantly over time and correlated significantly with TAC trough levels (p = 0.031). UCa/Cr values normalized by the third-month post-OLT, decreasing significantly over the time (p = 0.000) but did not correlate with TAC troughs. At three months post-OLT, 65.2% of patients needed antihypertensive therapy, and no patients needed more than one antihypertensive treatment after one yr. Despite nephrotoxic side effects in the early postoperative phase, this study shows that 65.5% patients had a normal renal function by three yr post-OLT. Tubular indices correlated with TAC trough levels.