Ascaris lumbricoides infestation in the liver and biliary tract causes various clinical manifestations due to the migration of larvae and adult organisms. Parasites in the bile ducts cause obstruction and such complications as cholecystitis, cholangitis and liver abscesses. We report the US findings of biliary ascaridiasis as observed in a series of 13 children over a 3-year period. The patients (6 females and 7 males) presented hepatosplenomegaly, abdominal distension, right subcostal pain; 3 of 13 exhibited subicteric features and fever. The US features of Ascaris lumbricoides infestation are: hyperechoic linear images due to parasites within the dilated bile ducts, target images; mobile hyperechoic linear images within the gallbladder; intrahepatic abscesses with different features and sizes. Microscopic sections of hepatic tissue show inflammatory infiltration around the Ascaris eggs. Emergency surgery is sometimes to be performed. The value of US, as we assessed it, has been already stressed by other authors.