Electrical stimulation of the central stump of a divided cutaneous nerve (which evokes a galvanic skin reflex) leaves behind a long-lasting inhibition of the galvanic skin reflex evoked by restimulation of the same nerve. The inhibition lasts for 20-35 sec. The inhibitory effect on the galvanic skin reflex is not of the same degree in all 4 extremities. It is least intense and of shortest duration in the pad of the limb being stimulated, most intense and of longest duration in the limbs at the other end of the body. After severance of the spinal cord, this post-stimulatory long-lasting inhibition of the galvanic skin reflex disappears except when the interval between the 2 periods is shorter or equal to 5 sec. When the amplitude of the spinal galvanic skin reflex is increased by asphyxiation of the animals the poststimulatory long-lasting inhibition remains absent. These facts warrant the conclusion that the observed post-tetanic long-lasting inhibition of the galvanic skin reflex is supraspinal in origin.