The cerebrovascular (CVD) and coronary artery (CAD) are focused as the primary cause for sudden death in Japan. The common risk factor for CVD and CAD is concerned atherosclerosis. We investigated the back ground of both CVD and CAD. The research was conducted on 240 patients of CVD treated by hospitalization and on 274 patients of CAD treated by PTA, stenting, and CABG in our institute. As the risk factor of atherosclerosis, the life style diseases (hypertension (HT), diabetes mellitus (DM), hypercho-lesterolemia (HC) ) and the patient's habit (smoking and alcohol) were investigated. 1) The CVD group had the life style disease in 73%. HT was seen in 65% DM in 28%, and HC in 19%. The combination rate of CAD was 22%. Obesity was seen in 48%. Forty-two percent of the patients had smoking experience and 46% had drinking alcohol history. Family history of the CVD was seen in 20%.2) The CAD group had the life style disease in 76% of 274 patients. HT was seen in 50%, DM in 32%, and HC 23%. And 19% of the patients had also the CVD. Obesity was revealed in 58%. Forty-seven percent of the patients had smoking experience and 22% of them had drinking alcohol history. Family history of the CAD was seen in 14%. 3) The incidence of the life style disease on CVD and CAD group is significantly higher than that of the health check-up group in our institute (21%).The incidence of the life style disease on the CVD and the CAD was significantly high. And approximately 20% of CVD and CAD were contained each other. Therefore, it is significantly important to check and treat the life style disease as the common risk factor of atherosclerosis for preventing the CVD and CAD.