We performed combined operation for patients who have both ischemic heart disease and valvular heart disease in 21 cases from January 1991 to October 1999. This operation was 3.1% of 682 cases of coronary artery bypass grafting and 5.0% of 416 cases of operation for valvular heart disease during that period. The mean age of these patients was 67.9 +/- 9.1 years. The average number of grafts in the coronary artery bypass grafting was 1.5 +/- 0.6. Aortic valve replacement was performed in 6 cases, mitral valve replacement in 10 cases and mitral valve plasty in 5 cases. Together with this combined operation, ascending aorta and aortic arch replacement was done in 1 case and abdominal aortic replacement in 2 cases. Three patients died due to postoperative aortic rupture, cerebral infarction or excessive surgical intervention in ascending aorta and aortic arch replacement. Combined operation for ischemic heart diseases and valvular heart diseases can safely performed, but it appears necessary to pay attention to arteriosclerotic lesions.