Although it is now recognised as a rare complication of cardiac surgery, constrictive pericarditis was diagnosed in three patients after coronary artery bypass surgery. The time interval between cardiac surgery and the development of constrictive features varied from two to six weeks. All three patients presented with severe congestive heart failure. Haemodynamic findings were characteristic of constrictive pericarditis. Pericardial thickening detected by computed tomography in one patient was useful in establishing a definite diagnosis. One of the patients had a serous constrictive effusive pericarditis, and surgical pericardial drainage was needed. The other patient underwent pericardiectomy with preservation of the grafts. The diagnosis of constrictive pericarditis should be considered in patients presenting with unexplained right sided heart failure after cardiac surgery.