The relationships between total serum cholesterol levels greater than 200 mg/dl or LDL-cholesterol levels greater than 155 mg/dl (135 mg/dl) and the incidence of coronary heart disease is well established. In contrast an inverse relationship could be shown between HDL-cholesterol levels and the frequency of cardiac death and non fatal myocardial infarction. It also seems to be possible that elevated triglyceride levels (greater than 200 mg) may represent an additional risk factor. Subsequent studies with a large number of patients and longterm observation proved, that fat-modified diets or drug treatment of hyperlipidemia results in a reduction of morbidity and mortality due to coronary heart disease, whereby the reduction of coronary events correlates directly to the degree of reduction of total cholesterol or LDL-cholesterol, respectively. This knowledge allows the clinician to identify persons at high risk for coronary heart disease and to start effective individual therapy in accordance with the recommendations of the European Atherosclerosis Society.