Dogs were bled into a reservoir which maintained arterial pressure at 35 mm Hg. All blood was reinfused after 30% of the maximum bleeding volume returned spontaneously to the animal. Cardiac outputs were measured by indicator dilution, and regional blood flows with an electromagnetic flowmeter on renal, femoral, and superior mesenteric arteries, and a common carotid with and without ligation of the external carotid. After the initial hemorrhage, total resistance about doubled. Renal, mesenteric, and femoral resistances increased greatly. Internal carotid resistance increased less than 2-fold. As hemorrhage progressed, femoral resistance decreased. All other resistances increased or were unchanged. Following reinfusion, renal and mesenteric resistances remained high, whereas other resistances returned to or below control levels. All but the renal resistances increased during a 2-hr period after reinfusion, as cardiac output fell. Irreversible shock sometimes occurred in the absence of these usual changes in flow distribution, and it was concluded that they were not essential to the development of irreversibility.