Hydatid disease is a parasitic disease caused by Echinococcus granulosus. The most frequent complication of pulmonary hydatid disease is the rupture of the cyst into a bronchus. In this article, we report the first case of hydatid cyst with spontaneous enucleation into the pleural cavity. A four-year-old boy admitted with dispnea, cough, high fever, and tension pneumothorax. A cyst was detected in the left hemithorax on chest computed tomography performed after chest tube insertion. During the operation, a free hydatid cyst was observed in the left hemithorax. The cyst was removed, the bronchial openings were repaired, and then capitonnage and total decortication were performed.