Patients with hepatic hydatid disease were examined by sonography (N = 62), plain radiography (N = 62), computerized tomography (CT; N = 25) and/or isotope scans (N = 31). The clinical presentation ranged from asymptomatic to right upper quadrant complaints and, rarely, remote symptoms. Plain radiology showed liver calcifications in 26% of the cases tested; half of the calcifications were in collapsed, flattened cysts. Sonography, the investigation of choice, since it is cheap, non-invasive and accurate, is particularly useful during the active stage of cyst development, when plain X-rays appear normal or show non-specific hepatomegaly. Sonography was used to categorize cysts as 'solitary univesicular' (23% of cases, echo-free, with sand or split wall), 'solitary multivesicular' (31%), 'solid echogenic mass' (10%), 'multiple' (21%); either uni- or multi-vesicular) or 'collapsed, flattened and calcified' (16%). Sonography was superior to CT in the investigation of the cyst wall, hydatid 'sand', daughter cysts, and the relationship of the cyst to the diaphragm. However, CT was superior to sonography in detecting gas within the cysts and minute calcifications and in anatomical mapping. The majority of the hydatid cases had multivesicular cysts. In Jordan, as in all endemic areas, a univesicular cyst of the liver should be considered a possible Echinococcus granulosus infection until proven otherwise.