Event-related potentials (ERPs) were recorded in young and elderly adults during the performance of an incidental encoding task (subjects were unexpectedly given a recognition test) followed by an intentional task (subjects expected the recognition test). Both tasks consisted of an encoding stage in which subjects classified words (natural/artificial) and a recognition stage in which they indicated whether the words were old (presented during the encoding stage) or new. In both groups and tasks, the ERPs, during encoding, differed as a function of subsequent recognition: the old words correctly recognized generated greater amplitude potentials than the incorrect ones. The memory processes expressed by these ERPs are preserved in elderly adults, independently of whether the information is incidentally or intentionally encoded.