A 27 year old woman who presented with upper abdominal pain was found on ultrasonography to have multiple liver cysts consistent with hydatid disease. Three years previously she had undergone evacuation of multiple infected liver cysts thought to be due to hydatid disease. Computed tomographic scanning supported the diagnosis of hydatid disease affecting the right lobe of the liver. At laparotomy the right lobe contained multiple cysts which were removed by right lobectomy. Histology revealed congenital dilatation of the intrahepatic bile ducts with fibrosis (Caroli's disease) but no evidence of hydatid disease.