The decision to treat hypercholesterolemia must take into account both the risk of death and myocardial infarction and the risk/benefit ratio of treatment. Nowadays there is convincing evidence that hypercholesterolemia in patients with previous myocardial infarction is an important prognostic factor: furthermore, the excess of risk due to cholesterol is consistently higher than that in the general population. Prospective studies demonstrated that cholesterol lowering treatment obtained either with diet or drugs can improve survival and quality of life in postinfarction patients. Experimental, clinical and angiographic studies suggested that cholesterol lowering therapy can produce both stabilization and regression of the atherosclerotic plaque. In view of this, the evaluation of cholesterol level must be part of the general work-up of patients with previous myocardial infarction. The satisfactory results obtained with diet suggest to try a dietary treatment in post-infarction patients with high cholesterol level before using drugs. Since there are no clear-cut upper values, the end point of treatment should be to lower cholesterol levels to the values recommended for the general population, although we believe that threshold values to be obtained in these subjects should be lower than those requested in primary prevention.