The clinical characteristics of 13 patients with cholesterol embolization are described. Embolization occurred spontaneously in 2 patients and after a vascular procedure in 11. Acute but vague symptoms were reported by 11 of the 13 patients; skin findings of purple toes or livedo reticularis and renal dysfunction were present in 12 patients, 5 of whom required dialysis. Blood pressure elevation occurred in all 13 patients, eosinophilia in 9 of 10 and elevated sediment rate in 5 of 6. Death occurred within 6 months in three patients. Two distinct patterns were observed: mild (five patients) and severe (eight patients). Compared with the severe pattern, patients with mild cholesterol embolization had early symptoms less frequently (two of five versus eight of eight), less severe renal insufficiency (serum creatinine 1.7 versus 7.4 mg/100 ml), less of an increase in blood pressure (22 versus 34 mm Hg) and later development of skin lesions (14 versus 6 weeks). Baseline blood pressure and development of eosinophilia were comparable in both groups. The presentation of cholesterol embolization is often subtle and may go unrecognized, particularly in its mild form. As vascular interventions increase in elderly atherosclerotic and hypertensive patients, so too will the incidence of this disorder. © 1990, American College of Cardiology Foundation. All rights reserved.