It was shown that the extreme susceptibility of adrenalectomized rabbits to hemorrhagic hypotension was mainly due to the absence of glucocorticoid.‘Take-up’ of shed blood in an elevated reservoir proceeded far earlier and more rapidly than in the non-adrenalectomized rabbit. This was accompanied by progressive diminution of pulse pressures, while the cardiac rate was reduced. At autopsy, no blood pooling was noticed except that due to acute right heart failure. Examination of right ventricular pressures revealed the presence of progressive secondary rise in systolic and diastolic pressures indicating an increase in the resistance of the pulmonary circuit. Pretreatment with physiological dose of Cortisone prevented these changes and inhibited the rapid progress of ‘take-up’. The significance of glucocorticoid therapy in hemorrhagic hypotension in rabbits which differed from that in dogs has been discussed.