It is well-known that mortality from coronary heart disease (CHD) is much lower in Italy and the Mediterranean countries than in Northern Europe and United States. Diet is one of the major environmental factors playing an important etiological role in different CHD incidence rates in these areas. The Seven Countries Study demonstrated that the average consumption of saturated fatty acids and cholesterol was directly related to CHD death rates, these being higher in Northern Europe and United States and lower in the Mediterranean countries and the Far East. Olive oil, particularly rich in oleic acid, could play a beneficial role in CHD prevention, as reported in the Italian Nine Communities Study carried out in the early 80s. Another multicenter study, the Intersalt Study, has clearly shown lower blood pressure in participants with lower intake of both sodium and alcohol and higher intake of potassium. Recent findings have also shown that two helping of fish per week and antioxidant vitamins, particularly vitamin E and beta carotene, are related to lower CHD incidence rate in the Mediterranean area compared to other countries. In conclusion, based on the reported findings, the Mediterranean diet represents an useful and effective mean for the prevention of CHD.