Three patients are described with hepatic involvement by Echinococcus granulosus, complicated by spontaneous rupture into the biliary tract. Clinical features consisted of upper abdominal pain, jaundice, fever, anorexia, and vomiting. Hepatomegaly and marked epigastric tenderness were consistently observed. Laboratory findings included obstructive liver function tests, leucocytosis, eosinophilia, and hyperamylasemia. Abdominal computed tomography, showing the cystic wall, the presence of wall calcifications, daughter cysts and wall enhancement, provided a correct diagnosis of hepatic hydatidosis in all patients. Dilatation of the bile ducts with the presence of intraluminal material was clearly shown by sonography and endoscopic retrograde cholangiography. These abnormalities were most frequently found in the common bile duct and in the left hepatic duct. On sonography, the intraluminal material appeared as amorphous, sludge-like hydatid sand, and as daughter cysts. On ERCP, the intrabiliary parasitic material appeared as non-homogeneous, irregularly shaped and mobile filling defects. Other findings at ERCP were displacement and distortion of intrahepatic bile ducts by the hepatic cysts and a mild dilatation of the pancreatic duct. In one occasion, evacuation of a daughter cyst through the papilla was observed. The therapeutic value of mebendazole and endoscopic sphincterotomy in our patients is discussed.