In an attempt to correlate xanthomas with atherosclerosis, the characteristics of serum lipid and lipoprotein profiles are explored in xanthoma patients. Xanthomas are classified into 5 subtypes: xanthelasma, planar xanthoma, papulo-eruptive xanthoma, tuberous xanthoma and tendon xanthoma. The clinical characteristics of xanthoma patients are summarized in the following, 1) Xanthelasma in 2 different types: one normolipemic and the other hyperlipidemic; of 30 xanthelasma patients, 5 were normolipemic. one of them had low HDL-cholesterol. 2) Tuberous and tendon xanthomas were all hypercholesterolemic, with serum cholesterol above 300 mg/dl and LDL-cholesterol above 255 mg/dl, while HDL-cholesterol was within normal range. 3) The xanthoma patients were generally not obese. 4) Their laboratory findings often showed such abnormalities as elevated levels in serum fibrinogen, LDH, CPK and uric acid. The resemblance of the clinical characteristics between xanthomas and atherosclerotic vascular disease, e.g., myocardial infarction, was striking. If the causation of their common tissue alterations by lipid accumulation is pathologically and biochemically defined, the correlation between those 2 kinds of disease can be. established.