This review mainly considers randomized studies where angiotensin-converting enzyme (ACE) inhibitors were compared with other antihypertensive drugs in terms of objectively assessed cognitive function, subjectively evaluated cognitive function, work performance, and general vitality. An overall assessment of the data suggests that ACE inhibitors may improve performance on tests of alertness but it is unlikely that they produce either deleterious or beneficial effects on memory. On the other hand, methyldopa interferes with cognitive function and work performance. Propranolol was also associated with impairment of activity and satisfaction at work. In subjective evaluation of cognitive function, two trials suggest an increased reporting of impairment with nifedipine but this has not yet been confirmed. Vitality was reduced on both methyldopa and propranolol. It is concluded that the ACE inhibitors, in common with atenolol and verapamil, do not appear to have any major effects on cognitive function in hypertensive patients.