A randomized single-blind study was designed to compare the performance on memory tests requiring recall of information relevant to everyday life of two groups of hypertensive patients. One group of 13 patients were taking a beta-adrenoceptor blocker (atenolol) and the other group of 12 patients received the angiotensin-converting enzyme inhibitor (enalapril). The results suggested that when compared with placebo the group of patients treated with enalapril showed no changes in memory function, whilst there was a mild, but consistent deficit in the group taking atenolol.