According to the Vital Statistics Report published by the Japanese Ministry of Health and Welfare, heart disease and cerebrovascular disease are the main causes of death in Japan. The main pathological finding in these diseases is atherosclerosis and the main risk factors, besides the patient's age and diathesis, include hyperlipidemia, hypertension, diabetes, obesity and smoking. Among the aforementioned various risk factors, hyperlipidemia play a crucial role at the stage of atherosclerosis. The main pathological findings in atherosclerosis include abnormal reactions of neutrophils, lymphocytes and monocytes/macrophages, vascular smooth muscle cells and vascular endothelial cells, and the accumulation of cholesterol ester in the arterial wall. Previously, Mg(2+) deficit and the lower blood concentration of Mg(2+) was a frequent in patients with the main risk factors, hyperlipidemia, hypertension, diabetes, and obesity. Magnesium is necessary the activity of lecithin cholesterol acyltransferase (LCAT) and lipoprotein lipase (LPL), which lowers triglyceride levels and raises HDL-cholesterol levels. Moreover, Mg(2+)-ATP is also the controlling factor for the rate-limiting enzyme in the cholesterol biosynthesis, which associated with cholesterol levels. In this article, we first discuss the effect of Mg(2+) deficit on atherosclerosis, especially hyperlipidemia in bloodstream and liver. Then, based on recent studies including our own, we describe the Mg(2+) deficit and the relationships between risk factors for atherosclerosis, hypertension, oxidative stress, cholesterol reverse transport system, and the molecular mechanisms, especially peroxisome preoliferator-activated receptor (PPAR), which have the pleiotropic effect in atherosclerosis. The mechanism is likely the effect of Mg(2+) on atherosclerosis.