36 patients aged 65 years or more, who underwent mitral valve replacement in the Department of Cardiac Surgery, Medical University of Łódź in 2000, were assessed. This group consisted of 22 women (61.1%) and 14 men (38.9%). The mean age of the patients was 68.5 years (+/- 2.96, age range from 65 to 76 years). The analysis of preoperative clinical state of the patients revealed prevalence of diabetes mellitus in 19 pts (52.78%), chronic bronchitis in 9 pts (25%), arterial hypertension in 14 (38.89%), pulmonary hypertension in 21 pts (58.33%), atrial fibrillation in 25 pts (69.44%), ventricular arrhythmia in 2 pts (5.56%) and cigarette smoking in 15 pts (41.67%). The mean left ventricular ejection fraction was 48.89% (+/- 9.26, from 30% to 70%). All patients were operated on cardiopulmonary by-pass and cardioprotection was obtained by the use of cold crystalloid cardioplegy solution based on St. Thomas Hospital formula. 6 patients (16.67%) underwent myocardial revascularization procedure simultaneously. In early postoperative period the following complications were observed: death--6 (16.67%), low cardiac output syndrome--5 (13.89%), need of use of intraaortic contrapulsation--2 (5.56%), need of use of inotropic agents--9 (25%), respiratory failure with the need of prolonged intubation--4 (11.11%), acute renal failure--4 (11.11%), stroke--2 (5.56%), need of temporary cardiac pacing--5 (13.89%), need of rethoracotomy--1 (2.78%). The results of mitral valve replacement procedures in patients over 65 years are less satisfactory than those of aortic valve replacement procedures in the same age group, however deaths considered patients with number of risk factors. The older age of the patients should not be treated at the moment as a contradiction to the cardiac surgery, but should be considered as a one of many risk factors.