Objective: To determine the location and radiological characteristics in children with abdominal hydatid disease (HD). Materials and methods: Thirty-one children (average age: 7.2 years) with abdominal HD were studied. The number, location, diameter and internal architecture of the cysts were assessed with abdominal ultrasonography (US) and computed tomography (CT). Density measurements and enhancement patterns were determined on CT. Results: Twenty-one children had hepatic HD. The remaining 10 children had both hepatic and extrahepatic cysts. There were splenic cysts in five children, peritoneal cysts in two children and combined splenic and peritoneal cysts in three children. The most common site of the cysts was the liver (64%), followed by the spleen (20%) and the peritoneal cavity (16%). The seven intraabdominal cysts, which were not detected by US, were 20 min or less in diameter. Conclusion: CT may demonstrate additional small intrahepatic or unsuspected extrahepatic cysts. Although rare, splenic or peritoneal hydatidosis should be included in the differential diagnosis of a cystic splenic or peritoneal lesion. Familiarity with atypical locations of HD may be helpful in making a prompt, accurate diagnosis. We think that in particular patients, especially those who had diagnostic problem and who are under surgical planning, CT should be performed additionally. (C) 2004 Elsevier Inc. All rights reserved.