It has been reported by some investigators that pressor response of rabbits to sympathetic ganglionic stimulants was weak. In this paper it was attempted to investigate this problem more thorouglhy in urethane anesthetized rabbits. 1) In rabbits the approximate doses to elicit increase of about 20 mmHg of blood pressure were 100μg/kg with DMPP, 50μg/kg with Wy-615, 500μg/kg with TMA and with nicotine. The pressor activity of these substances was markedly augmented by treating animals with syrosingopine. 2) In adrenal-ligated rabbits pressor activity of the substances was markedly reduced. Treating the adrenal-ligated animals with syrosingopine augmented significantly the pressor activity of these substances except DMPP. Direct injection of DMPP and TMA into the adrenal produced mole pressor response than intravenous injection did. These date suggest that DMPP has greater effect on the adrenal medulla than the other substances. 3) In vagotomized and atropinized rabbits the pressor activity of these compounds was more marked than in normal rabbits. 4) The above facts indicate that the pressor activity of the ganglionic stimulants in rabbits was definitely low than in cats and dogs. The low responsiveness of the rabbits to these agents was discussed in the light of catecholamine releasing mechanisms, and extraganglionic actions of these substances.