Infusion of endotoxin in chemically sympathectomized monkeys caused a fall in the mean aortic pressure, but the cardiac output, stroke volume, and central venous pressure were well maintained. Endotoxin-induced tachycardia in monkeys with functional sympathetics was not seen in the sympathectomized animals. Infusion of dopamine improved the hemodynamic and cardiovascular status, probably by causing vasoconstriction of the splenic and hepatic artery where the pooling of blood is believed to occur in endotoxin shock. However, these beneficial effects were not apparent when dopamine was administered in the chemically sympathectomized animal infused with endotoxin. Since chemical sympathectomy did not affect the endotoxin-induced decline in the systolic and mean aortic pressure or the severity of the endotoxin shock, it is suggested that catecholamines may not be the primary initiator or trigger substances in endotoxin shock.