Among 24 patients with esophageal perforation treated during the past 6 years, 3 patients developed pericarditis with effusion as a life-threatening complication. In the first patient pericarditis was found at autopsy, the diagnosis having been suspected but not proved during life. In the other 2 patients pericardial decompression was performed and both survived. Common denominators in the 3 patients were delayed diagnosis and treatment of the perforation, with resultant empyema. Further, the diagnosis of pericarditis with effusion was difficult and delayed, because mediastinitis and associated pleuritis and pneumonia obscured the cardiac silhouette on chest roentgenogram. It is recommended that a high index of suspicion of pericarditis be maintained in patients with esophageal perforation, especially in those in whom the perforation is diagnosed late.