Measurement, during reactive hyperemia, of the systolic slope of the pulse rate as recorded from a pneumatic cuff applied to the calf, appears to differentiate sharply normal subjects from arteriosclerotic subjects. There is slight overlap between the two groups for systolic slope at the foot and for mean pulse deflection at either level. Characteristic low values for systolic slope were obtained in all the arteriosclerotic subjects with symptomatic occlusion, and in limbs labeled as "normal" as opposed to "unilateral" disease. The test appears to depend upon arterial constriction or rigidity, with or without a pressure gradient, and should thus be more sensitive for identifying early disease than tests based upon pressure changes alone. This simple method is proposed for the epidemiological evaluation of arteriosclerosis. Its validity in predicting symptomatic disease will require further prospective studies.