A 43-year-old man with alcoholic cirrhosis and chronic alcoholic pancreatitis was referred for evaluation of chest pain and an enlarging pleural effusion. Computed tomography revealed a bilateral pleural effusion and longitudinal multilocular pancreatic pseudocysts extending to the posterior mediastinum along the esophagus. He was diagnosed with a mediastinal pancreatic pseudocyst rupturing into the pleural cavity and was initially treated with endoscopic ultrasound-guided trans-gastric drainage. After 4 months of stable disease, dysphagia and a severe cough developed due to an esophageal stricture and main bronchial fistula. Considering the inadequate drainage, the trans-gastric drainage stent was surgically exchanged for a percutaneous external drain and the bronchial fistula was repaired using an intercostal muscle flap. After improvement of the mediastinal abscess and the symptoms, he was discharged on post-operative day 72. Two years post-operatively, he is in good health with no recurrence. We herein report a rare case of a bronchial fistula and esophageal stricture after endoscopic trans-gastric drainage of a mediastinal pancreatic pseudocyst. Endoscopic trans-gastric drainage is an effective treatment for mediastinal pancreatic pseudocysts, but it is important to provide appropriate alternative treatment depending on the course of treatment.