NAP (Asn-Ala-Pro-Val-Ser-Ile-Pro-Gln) has neuroprotective, memory enhancing, and neurotrophic properties. NAP is a short peptide sequence derived from the recently cloned, activity-dependent neuroprotective protein. The current study was designed to evaluate NAP activity in normal middle-aged animals to further assess NAP's breadth of neuroprotection. NAP was administered by inhalation. Results showed that in the paradigm of the Morris water maze, assessing short-term memory, only the NAP-treated middle-aged rats and not placebo-treated rats showed significant improvements by the end of the testing period. These results suggest efficacy for NAP in normal aging that is associated with accumulating environmental and genetic toxic factors.