26 cases of ischaemic mitral regurgitation (MR) were treated by combined surgery: mitral valve replacement (MVR) and coronary bypass grafting (CBG). This type of operation is not common (1.3 p. 100 of all operations) and is usually reserved for men (21 cases) of middle age (average 59 years). A half of the cases had suffered previous myocardial infarction (MI), an average 5 months before surgery (range 20 days to 2 years). The other half had severe angina or ECG changes of myocardial ischaemia. 23 patients were in Class IV (15 patients) or Class III (8 patients) of the NYHA classification. 6 of the cases required intraaortic balloon pumping. Mitral regurgitation was severe () in half of the cases with a raised pulmonary capillary (mean V wave = 52 mmHg) and systolic pulmonary artery pressures (mean = 47 mmHg: exceeding 60 mmHg in 7 cases). The coronary lesions were severe in 18 patients (12 cases of double and 6 of triple vessel disease including 2 cases of left main stem stenosis). Ruptured chordae were found in 11 cases and papillary muscle necrosis in 4 cases. Surgery comprised MVR with 12 bioprostheses and 14 mechanical prostheses. 33 CBG were performed (anterior wall: 15 cases, posterior wall: 11 cases). In addition, one tricuspid annuloplasty and 3 ventricular aneurysmectomies were carried out. The hospital mortality was 15.4 p. 100. The main causes of morbidity were low output states and postoperative MI (2 cases).(ABSTRACT TRUNCATED AT 250 WORDS)