Introduction: Mediastinal tumor are uncommon entity they present a major anesthetic challenges due to major  airway and vascular compression. Case Report: A 60yr, old diagnosed with posterior mediastinum tumour at C7 level. Airway assessment revealed  mallampatti class IV. Blood investigations were within normal limit. Pulmonary function test revealed mild  obstructive disease. CT shows lesion in posterior mediastinum extending to right IJV with complete thrombosis  displacing trachea and thyroid. Triple lumen CVP line was secured. Difficult intubation trolley with tracheostomy  set was kept ready. Routine monitoring, left radial artery cannulation done. Patient was Preoxygenated,  Premedicated and Induced. 37F Left Double lumen tube was inserted and tube position confirmed with paediatric  fiberoptic bronchoscope. Patient was hemodynamically stable in the intraoperative period. Patient was reversed  and extubated uneventfully. Conclusion: Mediastinal tumor resection surgery is a very complicated and requires a team effect anesthesiologists,  surgeon and intensivist. A thorough pre-operative assessment of the patient should be done before the conduct of  anesthesia to avoid the complications due to posterior mediastinal mass. Keywords: Thoracotomy, One-Lung Ventilation, Mediastinal Tumor. Key Messages: Anesthetic management of patient with mediastinal tumor posted for thoracotomy and tumor  excision requires a double lumen ET tube for lung isolation and decrease in lung atelectasis. In this case a 60  year old male presented with mild symptoms and we highlight the usage of one lung ventilation in patient with  posterior mediastinal tumor