BACKGROUND: It has been suggested that adherence to a Mediterranean diet reduces all causes of mortality, especially death rates due to coronary heart disease. In this review we summarize the findings of observational studies that evaluated the effect of the Mediterranean dietary pattern in the primary and secondary prevention of coronary heart disease. MATERIAL/METHODS: We retrieved published results from prospective and case-control studies which evaluated the association between adherence to a Mediterranean diet and the occurrence of coronary heart disease outcomes. RESULTS: The benefits from the Mediterranean diet were significant in all studies. The reduction in the risk of coronary heart disease varied from 8% to 45%, depending on the increment used by the investigators in the presentation of their results. CONCLUSIONS: The systematically reviewed studies reveal a cardio-protective effect of the Mediterranean diet and point to this dietary pattern as highly appropriate for public health objectives.