Pancreatitis may be associated with thoracic complications, notably chronic massive pleural effusion (CMPE) and, rarely, pseudocysts with mediastinal extension (PME) and enzymatic mediastinitis (EM). Our personal experience with 14 cases of thoracic complications (nine CMPE, two PME associated with pleural effusion, and three EM of 670 patients who underwent surgery; of these, 191 had acute and 479 had chronic pancreatitis) during 16 years (1970-1986) is reported. In the patients with CMPE, the initial symptoms were progressive dyspnea eventually associated with cough and chest pain. In the PME cases, there was dysphagia associated with left subscapular pain and left chest pain. The initial signs in the patients with EM were sudden dyspnea, cyanosis, retrosternal pain, tachycardia, and acute heart failure. A fistula between the pancreatic ductal system and the pleural cavity in seven of the nine patients with CMPE was demonstrated by intraoperative pancreatography and/or cystography. On the contrary, preoperative endoscopic pancreatography demonstrated the sinus tract in only three of the seven. In both cases of PME, computed tomography (CT) provided a correct diagnosis that was confirmed at surgery. In the patients with EM, the diagnosis was suggested by the clinical appearance and was confirmed by the chest roentgenogram and by CT. All patients had operations after varying periods of unsuccessful 2-4-week-long conservative treatment. One patient with infected ascites died postoperatively. There were no thoracic recurrences of pancreatic disease among the other patients at a 10-month-10-year follow-up observation after surgery.