The Mediterranean diet has been hypothesized to reduce fatality among patients with coronary heart disease. We examined the association between the degree of adherence to the traditional Mediterranean diet and survival of persons with diagnosed coronary heart disease at enrollment, in a population-based prospective investigation of 1302 Greek men and women, who were followed up for an average of 3.78 years (the European Prospective Investigation Into Cancer and Nutrition cohort). Information on usual dietary intakes during the year preceding enrollment was recorded through a validated food frequency questionnaire. Adherence to the Mediterranean diet was assessed by a 10-unit Mediterranean diet score that incorporates the salient characteristics of this diet. Proportional hazards regression was used to assess the relation of overall degree of adherence to the Mediterranean diet with mortality overall or by cause (cardiac vs noncardiac). Higher adherence to the Mediterranean diet by 2 units was associated with a 27% lower mortality rate among persons with prevalent coronary heart disease at enrollment (total deaths, 131; adjusted mortality ratio, 0.73; 95% confidence interval, 0.58-0.93). The reduced mortality was more evident and amounted to 31% (total deaths, 85; adjusted mortality ratio, 0.69; 95% confidence interval, 0.52-0.93) when only cardiac deaths were considered as the relevant outcome. Associations between individual food groups contributing to the Mediterranean diet score and mortality were generally not significant. Greater adherence to the traditional Mediterranean diet is associated with a significant reduction in mortality among individuals diagnosed as having coronary heart disease.