This study describes a specific memory impairment in subjects taking either of two kinds of centrally active anti-hypertensive agents. Verbal memory impairment was present in hypertensive and normotensive patients taking methyldopa or propranolol hydrochloride, while hypertensive patients receiving only a diuretic did not show this deficit. Visual memory impairment was not seen in any of the groups tested. The majority of the subjects were unaware of their memory deficit, even when test results clearly revealed impairment. An earlier pilot study of 12 hypertensive patients receiving methyldopa or propranolol used a broad range of cognitive tests and also demonstrated impairment in verbal memory only, while other cognitive measures remained relatively unaffected.