The tapeworm Echinococcosis granulosus can cause parasitic disease in the human body. The definitive host for the adult form is usually dog, in the intestine of which tapeworm lives in large numbers. Hydatid cyst is caused by water and food polluted with parasites' larva, or direct contact with dogs. Humans can rarely become intermediate hosts when they are infected by ingesting contaminated food, or by contact with infected animals. We report a pediatric case with cerebral and cardiac involvement. The patient had been operated with the diagnosis of primary multiple cyst hydatid disease one year before. Cysts were delivered by the Downling technique at the operation without rupture, but they relapsed in the same area. The first origin was investigated by thorax-abdominal computed tomography, echocardiography, abdominal ultrasonography. The focus of the cyst was found in the left atrium. This report has been written to stress concomitant brain and cardiac involvement of hydatid cyst disease.