The aim of this study was to determine the long term outcome of renal glomerular and tubular functions in children receiving an LT for WD. Renal functions were examined in nine children with WD before and long after LT and compared with those of nine liver transplanted children with hepatic diseases other than WD. The duration of follow-up was at least two yr for both groups. GFR, fractional TRP and tubular maximum rate of phosphate reabsorption in relation to GFR (TP/GFR) as well as daily protein and Ca excretion were studied in both groups before and after LT. Pretransplant mean GFR, TRP and TP/GFR were significantly lower in the study group than the controls. A significant increase in the post-transplant TRP and TP/GFR was observed in the study group and the difference between the groups disappeared during the long term follow-up. Urinary protein excretion decreased in both groups after LT. Tubular dysfunction is frequent in patients with WD. LT for hepatic failure secondary to WD is a lifesaving procedure correcting the underlying hepatic defect as well as renal defects.