[male] rats were adrenalectomized at 27-35 days of age and maintained on 1% NaCl as drinking water. Hypophysectomy was performed 7-10 days later, when the rats were 39-42 days of age. Due to the extremely delicate condition of the doubly operated rats, in contrast to hypophysec-tomized rats, attempts were made to improve their survival by means of carbohydrate supplementary to the diet. Glucose was injected intraperit. in a 10% soln. made up in physiological saline. Sucrose (5%) was added to the drinking water, Adrenalectomized-hypophysectomized rats thus supported still had a conspicuously higher mortality than hypophysectomized rats. Pituitary growth hormone administered to these rats substantially decreased this mortality. Adrenalectomized-hypophysectomized rats showed the same sensitivity to pituitary growth hormone as characterizes hypophysectomized rats. Response to growth hormone was measured by increased body wt., skeletal dimensions and thickness of epiphyseal cartilage.