For decades, hyperlipidemia, and more precisely hypercholesterolemia, has been considered as a major coronary heart disease factor. The relationship has been established both at the group and at the individual levels, and cholesterolemia lowering by diet or drugs is followed by a coherent decrease of risk. These facts are recalled from examples. All these results suggest that hypercholesterolemia is implied in the development of the atherosclerotic lesions which would represent the true biological marker of risk. However, as long as this marker cannot be measured directly among populations, the prediction of the individual risk will remain inaccurate and the indications of preventive treatment will not have a scientific basis. Progress might be obtained from the improvement of noninvasive techniques for coronary atherosclerosis detection, on the one hand, and from the study of biological heterogeneities in lipoprotein metabolism which might explain the prognostic heterogeneity among individuals, on the other hand.