In the past years the number of patients with combined treatment of the heart valves and coronary arteries rised as well as the patients age did. In 1980-1987 the rate of patients with aortic valve replacement and simultaneous aorto-coronary bypass was 10.9% in those who underwent aortic valve replacement and 2.9% in those who had aorto-coronary bypass operation. Since 1988 the ratios changed to 18.2% and 4.9%. For the calculation of the operative risk of the combined operative treatment (AVR + CABG, MVR + CABG) we compared these groups with those patients with isolated operations (MVR, AVR, CABG). We studied all patients during 1980 and July 1989. The hospital mortality of combined procedures was significantly increased. The mortality among female patients was higher as compared to the male group. The age of patients treated by the combined procedures was higher as compared to the isolated procedures. The mean age of the patients which died was severely increased as compared to the isolated procedures. However, in the combined procedures this increase was not as pronounced as in the isolated groups. Patients with combined procedures had a higher NYHA class. The risk factors of the combined procedures were comparable to isolated CABG.