The retrospective study of 115 children in whom a successful portosystemic shunt was carried out for portal hypertension, provides the following conclusions: 1) Patency of the shunt must be checked by esophageal endoscopy, six months postoperatively. A patent shunt can be expected when the size of the spleen and/or thrombocytopenia improve in the early post-operative period. Early ultrasound examination is also very useful in that respect. 2) None of the children with extrahepatic portal vein obstruction or congenital hepatic fibrosis presented with clinical signs of portal systemic encephalopathy (PSE). 3) Eight of 30 children with cirrhosis presented with one or more clinical episodes of PSE. Some were transient allowing for a normal diet to be resumed later on. 4) It is thus advisable to give children with cirrhosis a low protein diet in the months after surgery. Protein content of the diet can usually be increased progressively over a period of one to two years. 5) Whenever splenectomy is necessary, it is mandatory to prevent pneumococcal infections with the pneumococcal vaccine and daily treatment with oral penicillin.