Forty-four hemodynamic studies were carried out in 19 patients with chronic renal failure in the azotemic state, as well as 16 studies in 16 surgical patientswho did not have renal disease but who exhibited some degree of pulmonary insufficiency. The results show that the hyperdynamic circulatory state associated with both diseases can be differentiated only by the anemia of chronic uremia and the frequent radiological evidence of interstitial pulmonary edema associated with hypervolemia. It is clear from these data that a physician is readily able to ascertain hypervolemia and interstitial pulmonary edema with the ordinary sphygmomanometer a t the bedside of a chronically uremic patient. Possible mechanisms of the hemodynamic response t o chronic renal failure as ascertained in this study are discussed.