THE CLINICAL significance of atheroembolism from aortic and arterial atheromatous plaques to various organs and tissues has not been appreciated until fairly recently. Embolization of atheromatous material has been seen with increasing frequency, and it is now recognized that impaction of this material within small arteries and arterioles may be manifested by (1) paroxismal ischemic changes of the feet and legs with pain, livedo reticularis, and gangrene despite adequate arterial pulses1-3; (2) hypertension and impaired renal function4-6; (3) abdominal pain, gastrointestinal hemorrhage, and pancreatitis7,8; and (4) occasionally neurological symptoms and retinal emboli.9-12 The purpose of this paper is to describe the clinical and pathologic findings in five patients with most of these manifestations and in whom the diagnosis of atheroemboli was made. The use of diagnostic muscle biopsies and the clinical significance of embolization to the renal and gastrointestinal systems are emphasized. Report of Cases Case 1 (MSH 68147). —A