The low death rate from coronary heart disease among the Greenland Eskimos has been ascribed to their high fish consumption. We therefore decided to investigate the relation between fish consumption and coronary heart disease in a group of men in the town of Zutphen, the Netherlands. Information about the fish consumption of 852 middle-aged men without coronary heart disease was collected in 1960 by a careful dietary history obtained from the participants and their wives. During 20 years of follow-up 78 men died from coronary heart disease. An inverse dose-response relation was observed between fish consumption in 1960 and death from coronary heart disease during 20 years of follow-up. This relation persisted after multiple logistic-regression analyses. Mortality from coronary heart disease was more than 50 per cent lower among those who consumed at least 30 g of fish per day than among those who did not eat fish. We conclude that the consumption of as little as one or two fish dishes per week may be of preventive value in relation to coronary heart disease.