The term ``heat shock protein(Hsps)`` was derived from the fact that these proteins were initially discovered to be induced by hyperthermic conditions. In response to a range of stressful stimuli, including hyperthermia, immobilization, UV radiation, amino acid analogues, arsenite, various chemicals, and drugs the mammalian brain demonstrates a rapid and intense induction of the heat shock protein. Moreover, Hsps were expressed on the various pathological conditions including trauma, focal or global ischemia, hypoxia, infarction, infections, starvation, and anoxia. Especially, Hsp25 has a protective activity, facilitated by the ability of the protein to decrease the intracellular levels of reactive oxygen species(ROS) as well as its chaperone activity, which favors the degradation of oxidized proteins. Recently, it has clearly demonstrated that Hsp25 is constitutively expressed in the adult mouse cerebellum by parasagittal bands of purkinje cells in three distinct regions, the central zone(lobule VI-VII) and nodular zone(lobule IX-X), and paraflocculus. The Mongolian gerbil has been introduced into stroke study model because of its unique brain vasculature. There are no significant connections between the basilar?vertebral system and the carotid system. This anatomy feature renders the mongolian gerbil susceptible to forebrain ischemia-induced seizure. The present study is designed to examine the pattern of Hsp25 expression in the cerebellum of this animal in comparison with that in mouse.