This study sought to establish whether administration of dehydroepiandrosterone (DHEA) or its sulfate derivative to aged mice could effectively correct the immunosenescent phenotype. Supplemental DHEA sulfate and topical DHEA fully corrected the age-associated dysregulated production of T cell lymphokines by cells from all of the different lymphoid organs tested. Either DHEA or DHEA sulfate supplementation promoted enhanced antibody responses against recombinant hepatitis B surface antigen (rHBsAg) by the aged recipients when incorporated directly into the vaccine. When DHEA was provided either topically or was incorporated directly into vaccine, vigorous primary and secondary antibody responses were detected in the aged mice given a single administration of DHEA, regardless of the mode of administration. It was also established that DHEA treatment could enhance specific antibody responses to rHBsAg in aged animals that had previously not been effectively immunized by conventional vaccination procedures.