Background: A pancreatic pseudocyst is one of various complications occurring in acute or chronic pancreatitis. It is usually located in the retroperitoneal space near the pancreas. However, other unusual locations are also possible. Jones initially described the mediastinal pseudocyst in 1940. Since then, fewer than 50 cases have been reported. A diagnosis of a mediastinal pseudocyst is accomplished by imaging studies revealing the cystic nature of the mass with evidences of acute or chronic pancreatitis. There is some controversy regarding the appropriate management of mediastinal pseudocyst because of the high mortality and morbidity after surgical management. Here we report a case of a mediastinal pancreatic pseudocyst found in a patient with asymptomatic alcohol-related pancreatitis complicated by the development of a mediastinal pseudocyst, which quickly resolved after endoscopic retrograde pancreatic and biliary drainage and subcutaneous injection of a somatostatin analog(octreotide acetate) without any complications.