Cases with cardiac hydatid cyst disease are uncommon, being approximately 0.2-2% of all cases. Most cardiac hydatid cysts are located in the interventricular septum or left ventricular wall. Pericardial location is very rare. We report on a 12 year old girl with pericardial hydatid cyst disease who was otherwise asymptomatic, having no cardiac symptomatology. Unfortunately the course of her disease was fatal. This is the first report of uncommon localized hydatid disease with a fatal outcome.