As key molecular chaperone proteins, heat shock proteins (HSPs) represent an important cellular protective mechanism against neuronal cell death in various models of neurological disorders. In this study, we investigated the effect as well as the molecular mechanism of geldanamycin (GA), an inhibitor of Hsp90, on MPTP-induced dopaminergic neurotoxicity, a mouse model of Parkinson’s disease. Neurochemical analysis showed that pretreatment with GA (via intracerebral ventricular injection 24 hr prior to MPTP treatment) increased residual dopamine content and tyrosine hydroxylase immunoreactivity in striatum 24 hours after MPTP treatment. To dissect out the molecular mechanism underlying this neuroprotection, we showed that the GA-mediated protection against MPTP was associated with a reduction of cytosolic Hsp90 and an increase in Hsp70, with no significant changes in Hsp40 and Hsp25 levels. Furthermore, in parallel with the induction of Hsp70, striatal nuclear HSF1 levels and HSF1 binding to HSE sites in the Hsp70 promoter were significantly enhanced by the GA pretreatment. Together these results suggest that the molecular cascade leading to the induction of Hsp70 is critical to the development of MPTP-induced neurotoxicity in the brain and pharmacological inhibition of Hsp90 may represent a potential therapeutic strategy for Parkinson’s disease.