Introduction: Introduction: The complicated hydatid cyst of the lung is defined as any cyst ruptured in the bronchi tree or in the pleural cavity, infected, and rarely in the pericardial cavity. The aim of this study was to evaluate the problems of complicated pulmonary hydatid cyst, including presentation, diagnosis choice of surgical methods. and complication of delay in surgical treatment of pulmonary hydatid cysts. Methods: Between 2016 and 2021, 192 operations operated for pulmonary hydatid cysts, 42 of these patients were complicated hydatid cyst. Presentations were cough, chest pain and dyspnea.Diagnosis tools were CXR and CT-scan of chest. surgical approach was a posterolateral thoracotomy and anterolateral thoracotomyin all patients; a phrenotomy in eight patients and one-stage bilateral thoracotomy in six patients. Results: In 18 patients (67.5%), there were single hydatid cysts; whereas 4 patients (32.5%) had multiple cysts.12 patients had bilateral cyst and 8 had both lung and liver and others organs, 6 patients had preoperative hydatid cyst history. Iatrogenic rupture of an intact hydatid cyst occurred in 4 patients. Extrathoracic involvement was apparent in 6 patients (27%). Intrathoracic but extrapulmonary involvement was apparent in 4 patients (16%). Conclusion: Complicated hydatid cyst may present with different clinical and radiologically manifestations as a primary lung tumor , pleural effusion ,empyema hydropneumothorax. In patients with suspicious lung masses in endemic area or history of a hydatid cyst in patients a complicated pulmonary hydatid cyst may be in differential diagnosis.