It is generally agreed that many factors may contribute to the development of coronary heart disease (CHD). The risk factors most agreed upon include both endogenous factors such as sex, age and genetic make-up and exogenous factors such as smoking, dietary habits and an affluent lifestyle. Serum lipids and lipoproteins play important roles. The rapid increase in CHD in several countries in the last decades and the drop in incidence during World War II in some western societies imply that exogenous factors are of importance, so that disease prevention should be possible. However, is the presently available information sufficient to act on, and what should be done? A questionnaire was sent to 211 scientists including epidemiologists, nutritionists and geneticists, doing research on atherosclerosis and lipids from both medical and experimental points of view to examine whether expert opinion is in agreement on approaches. Almost all agreed that there is a connection between diet and the development of CHD, between diet and plasma lipoprotein levels, and between plasma cholesterol and the development of CHD. There was greater disagreement and uncertainty about the role of plasma triglycerides. Of the 192 who answered, 176 (92%) stated that the present knowledge of the relationship between diet and CHD is sufficient to recommend a moderate change in the diet of an affluent society. Many of the recommendations for changes in daily diet listed in the questionnaire are commonly offered to the general public. Hence the low priority given to more polyunsaturated fat was rather surprising. There is some uncertainty about the benefits of recommending a high intake of polyunsatured fatty acids.