Fifty-five studies of cognitive side effects of beta-blockers were reviewed. Many of the studies were limited by small sample size, use of drugs out of the range of normal administration, failure to control for known confounders for neuropsychological evaluation, or lack of a crossover design. As a result, one needs caution in drawing conclusions on this topic. Nevertheless, given the widespread use of beta-blockers and the frequent allegations about their relative side effect profiles, it is appropriate to summarize the results of these disparate studies. Across all beta-blockers and all cognitive domains, the drugs led to improved functioning in 16% of observations and worsened functioning in 17%, with no significant effect in the rest. Memory, learning, and abstraction have been studied less frequently. The perceptual motor cognitive domain was the most widely studied and was frequently affected by these drugs. There was no consistent evidence of a trend for lipophilic drugs to impair this domain more than lipophobic drugs. There is some evidence that these drugs have a positive effect on complex task performance. The drugs also seem to increase sedation; however, in these studies there was no evidence for a differential effect across lipophilic vs lipophobic drugs.