Magnetic resonance imaging was evaluated in 12 patients with hydatid disease (Echinococcus granulosus). Patients also underwent real time ultrasound and computed tomography imaging. Clear images of hepatic hydatid cysts were produced by magnetic resonance imaging, and intracyst structures were demonstrated. Changes in the appearance of cysts were seen following chemotherapy. Whilst not cost effective at present, if further improvements allow differentiation of simple (epithelial) and hydatid cysts or viable and dead hydatid cysts this technique could be of clinical value.