A 42-year-old man was admitted complaining of dyspnea. Chest X-ray showed an increase in cardiac size, and echocardiography revealed a large volume of pericardial effusion. Pancreatic enzyme levels were elevated in both serum and pericardial effusion. Computed tomography and endoscopic retrograde pancreatography demonstrated a fistula connecting a pancreatic pseudocyst with the pericardium and the right pleural cavity. Massive pericardial and right pleural effusion is an extremely rare complication of chronic pancreatitis. In this case, computed tomography and endoscopic retrograde pancreatography were useful for diagnosing the fistula.