The gratifying results obtained with reconstructive surgery of the aorta and peripheral arteries in the treatment of occlusive lesions is evidence of restoration of blood flow toward normal.4-6 In general, clinical methods are adequate to assess the degree of change following resection or bypass of an occluded artery; however, it seemed to us that a quantitative measurement of the alteration produced by the disease on the one hand and by its operative correction on the other would provide interesting data relating to peripheral blood flow which might be clinically useful as well. This study was begun, therefore, to measure digital blood flow in the upper and lower extremities of patients with arteriosclerotic occlusive disease and aneurysms of the aorta and peripheral arteries. From among 25 patients in whom digital blood flow measurements were made, 9 have been selected to illustrate certain aspects of the study, and the data from