Seven patients with hydatid disease of the spleen were examined by radiography, ultrasound, CT, and in one case MR imaging. The observations were confirmed by patho-anatomic findings except in 2 patients where high indirect hemagglutination tests confirmed the diagnosis. In one patient primary, and in the others secondary, echinococcosis of the spleen was assumed to be present. Secondary hydatid disease of the spleen was caused by rupture of liver cysts with abdominal and pelvic dissemination. Ultrasound and CT findings of the cysts and cystic calcifications are described. In one patient MR imaging indicated prolapse of a splenic hydatid cyst into the left hemithorax, confirmed by patho-anatomic examination.