Sympathetic ganglionic stimulants (DMPP, Wy-615, TMA and McN-A-343) produced pressor response in chickens anesthetized with phenobarbital sodium. In adrenalectomized chickens the pressor activity of DMPP, Wy -615 and TMA was less than in normal chickens but that of McN-A-343 was unchanged. Hexamethonium (20 mg/kg) and chlorisondamine (5 mg/kg), ganglionic blocking agents, reduced the pressor response to DMPP and Wy-615 but did not abolish the response. The pressor effect of McN-A-343 was not potentiated by the ganglionic flocking agents, but abolished by atropine.