A 57-year-old man with a 3-year history of chronic pancreatitis was admitted to our hospital with upper abdominal pain. Based on examination findings, the patient was diagnosed as having pseudocysts in the pancreatic body and the mediastinum that were associated with acute aggravation of chronic pancreatitis. Because of the patient refused an operation, he was submitted to conservative management including intramuscular injection with somatostatin analogue of 100 microg/day. On the 14th day of the treatment, pleural effusion and pseudocyst in the pancreatic head were additionally diagnosed based on the findings of computed tomography, magnetic resonance imaging and other examinations, and the dose of somatostatin analogue was increased to 200 microg/day. As a result, on the 28th day of the treatment, pancreatitis was inactivated, and the pseudocysts in the mediastinum and the pancreas disappeared. The patient has been followed up for 15 months, and there has been no recurrence.