Previous experiments have reported deficits in cognitive performance following the administration of beta-adrenoceptor antagonists. These deficits have not appeared consistently, however, and it is not clear from previous studies whether changes in the central nervous system, rather than end-organ functioning, are responsible. The present experiment investigated the effects of beta blockade in a memory-search paradigm that distinguished the relatively central process of memory comparison from the more peripheral processes of stimulus encoding and response selection. Twenty-six adult men with mild essential hypertension received either a placebo or a beta blocker (atenolol or propranolol) for 2 weeks. Although beta blockade did occur in the active drug groups, there were no significant effects of the drugs on memory-search performance.