An expert round table discussion on the relationship between intake of n-3 polyunsaturated fatty acids (PUFA) mainly of marine sources and coronary heart disease at the 34th Annual Scientific Meeting of European Society for Clinical Investigation came to the following conclusions: 1. Consumption of 1-2 fish meals/wk is associated with reduced coronary heart disease (CHD) mortality. 2. Patients who have experienced myocardial infarction have decreased risk of total, cardiovascular, coronary, and sudden death by drug treatment with 1 g/d of ethylesters of n-3 PUFA, mainly as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The effect is present irrespective of high or low traditional fish intake or simultaneous intake of other drugs for secondary CHD prevention. n-3 PUFA may also be given as fatty fish or triglyceride concentrates. 3. Patients who have experienced coronary artery bypass surgery with venous grafts may reduce graft occlusion rates by administration of 4 g/d of n-3 PUFA. 4. Patients with moderate hypertension may reduce blood pressure by administration of 4 g/d of n-3 PUFA. 5. After heart transplantation, 4 g/d of n-3 PUFA may protect against development of hypertension. 6. Patients with dyslipidemia and or postprandial hyperlipemia may reduce their coronary risk profile by administration of 1-4 g/d of marine n-3 PUFA. The combination with statins seems to be a potent alternative in these patients. 7. There is growing evidence that daily intake of up to 1 energy% of nutrients from plant n-3 PUFA (alpha-linolenic acid) may decrease the risk for myocardial infarction and death in patients with CHD. This paper summarizes the conclusions of an expert panel on the relationship between n-3 PUFA and CHD. The objectives for the experts were to formulate scientifically sound conclusions on the effects of fish in the diet and the administration of marine n-3 PUFA, mainly eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), and eventually of plant n-3 PUFA, alpha-linolenic acid (ALA, 18:3n-3), on primary and secondary prevention of CHD. Fish in the diet should be considered as part of a healthy diet low in saturated fats for everybody, whereas additional administration of n-3 PUFA concentrates could be given to specific groups of patients. This workshop was organized on the basis of questions sent to the participants beforehand, on brief introductions by the participants, and finally on discussion and analysis by a group of approximately 40 international scientists in the fields of nutrition, cardiology, epidemiology, lipidology, and thrombosis.