A new technique is described for the determination of cholesterol in skin biopsies which is sensitive, practical and reproducible. The determination of cutaneous cholesterol is of clinical interest, because of its correlation with the degree of atherosclerosis. There was no correlation found between the blood total cholesterol and total triglycerides, and cholesterol and triglycerides determined in the skin biopsies. Determinations were carried out on several normal subjects, 7 long-distance runners, 34 hyperlipidemic patients. There was a significant increase with age of total skin cholesterol in the normal subjects, the values obtained with the long-distance runners had a tendency to be somewhat lower. All the patients investigated had higher cholesterol values than the normal controls or the sportsmen. This technique can be used therefore as a diagnostic tool to detect pathologies of skin lipids, or of tissue lipid metabolism, as for example in normolipidemic patients presenting corneal arcus or xanthelasmas.