Evidence is presented confirming previous observations in the dog that the physiological response to aldosterone of adrenalectomized rats is both an antinatriuretic and kaliuretic effect, while in intact rats the response to aldosterone is only a kaliuretic effect. Therefore, the antinatriuretic and kaliuretic components of the response to aldosterone may be separable. Both components of the physiological responses in both adrenalectomized and intact rats were greater in males than in females. (Endocrinology92: 989, 1973)