.....Here we explored the effects of intranasal administration of exogenous recombinant human Hsp70 (eHsp70) on lifespan and neurological parameters in middle-aged and old mice. Long-term administration of eHsp70 significantly enhanced the lifespan of animals of different age groups. Behavioral assessment after 5 and 9 mo of chronic eHsp70 administration demonstrated improved learning and memory in old mice. Likewise, the investigation of locomotor and exploratory activities after eHsp70 treatment demonstrated a significant therapeutic effect of this chaperone. Measurements of synaptophysin show that eHsp70 treatment in old mice resulted in larger synaptophysin-immunopositive areas and higher neuron density compared with control animals. Furthermore, eHsp70 treatment decreased accumulation of lipofuscin, an aging-related marker, in the brain and enhanced proteasome activity. The potential of eHsp70 intranasal treatment to protect synaptic machinery in old animals offers a unique pharmacological approach for various neurodegenerative disorders associated with human aging.