Coronary atherosclerosis begins with the impairment of endothelial function of anti-thrombosis, vasorelaxation, anti-proliferation, and anti-atherosclerosis. Endothelial dysfuction is induced not only by bio-chemical factors such as hypercholesterolemia, smoking, hypertension, and diabetes mellitus, but also by bio-mechanical factors, such as disturbance of laminar flow of blood stream. In addition to these conventional risk factors, new ones emerge as important factors for atherosclerosis, which include hyperhomocysteinemia, oxidative stress, and infectious agents. The results of the several ongoing trials of antibiotics, antioxidant, and vitamins for prevention of cardiovascular diseases will elucidate implications of these new risk factors for coronary atherosclerosis.