Knife-cut lesions were used to assess the participation of the subfornical organ (SFO) in the central pressor action of intravenously administered angiotensin. Knife-cuts of the ventral stalk of the SFO significantly attenuated pressor responses during infusion of 3 doses of angiotensin, although responses to bolus injections were unaffected. These results are consistent with previous work in implicating the SFO as an important mediator of the central pressor action of circulating angiotensin.