An extremely rare manifestation of atherosclerosis is described. Two women, aged 57 and 55, presented with upper extremity hypertension and diminished femoral pulses. Plain radiography and total angiographic visualization of the aorta demonstrated focal highly obstructing intraluminal masses containing heavy flocculent calcification in the upper descending thoracic (case 1) and the thoracoabdominal aorta (case 2) producing a significant pressure gradient. The acquired coarctation due to calcified thrombus was relieved by resection and graft replacement in one and placement of a thoracoabdominal bypass graft in the second patient.