SummaryThe author discusses the results of a study made in collaboration with 125 clinicians on the practical value of blood cholesterol determination.One prevailing opinion is the lack of significance of this determination in arteriosclerosis. The recent biological acquisitions in the studv of the dys-lipidemias which present a clinical application are briefly considered. The percentage of cholesterol bound to betalipoproteins gives a better notion of the metabolic troubles of arteriosclerosis than do the simple screening tests. The identification of a soluble trichlorethvlene cenapse may prove useful in the future. The stage in the evolution of a case of arteriosclerosis furthermore, seems to have a close correlation with the coheparin clearing factor.