Synthetic angiotensin II (SA II) is an effective pressor agent in hypotensive states. In this experience the theoretically expected advantages over available agents have been demonstrated. SA II was administered to 14 patients with hypotensive states of varied origin and was effective to some degree in all, including those who were relatively unresponsive to other pressor agents. Responsiveness to SA II tended to diminish with deterioration of clinical status of patients who did not survive and to increase as patients capable of recovery improved. Perhaps characteristically, responses were poor or briefly sustained in four patients with portal cirrhosis. The agent seemed most helpful in two of three patients with apparent bacteremic shock.