From december 1984 to december of 1991, 12 children underwent on orthotopic liver transplantation (OLT): 6 had extrahepatic biliary atresia (EHBA), 2 had Byler disease, 2 hepatocellular carcinoma (HCC), 1 Alagille Syndrome and 1 had a hyperacute Wilson disease. The children, transplanted for the most part a broad, return for observation 3 months after OLT. A patient with hyperacute Wilson's Disease had 2 emergency OLTs and died of sepsis (due to Aspergillus); another with EHBA, operated for hepatoportoenterostomy, without result, died after OLT because of a ruptured aortic aneurysm. The other 10 are living with a variable follow-up between 8 months and 7 years. The post-operatory complications were present in 4 cases: in the same patient (15 months old) a hepatic artery thrombosis and then a portal vein thrombosis were observed; 3 patients had to have their biliary-digestive anastomosis redone. 7 of 10 patients had acute rejection. During the first month after OLT infection episodes were mostly due to bacteria (G-), Candida and Pneumocystis carinii (blood and intraabdominal sepsis). In the second period (1-3 months) there were viral infections, in particular CMV. An emergency transplanted patient, incompletely vaccinated, developed HBV infection. During long term follow-up (after the 3rd months from OLT) the children usually have mild infections of the respiratory and urinary tracts. After 1 year, they have a mean annual growth velocity that is between the 50th and 90th percentile. They showed a good rehabilitation. Their hospitalizations rate was reduced if compared with the period before OLT. Health, motor function and general behavior improved significantly.(ABSTRACT TRUNCATED AT 250 WORDS)