Objective To study the effects of pioglitazone on the expressions of peroxisome proliferator- activated receptor-γ (PPAR-γ) in hippocampus and hypothalamus of diabetic rats and to explore the association between pioglitazone and cognitive function. Methods Thirty male SD rats were equally randomized into control group (C group)， diabetic group (D group) and diabetes+pioglitazone group (DP group). The spatial learning and memory function were tested by Morris water maze after 8 weeks. Expressions of PPAR-γ in hippocampus and hypothalamus were detected by Western Blot. Results In the Morris water maze， escape latencies of D group increased significantly compared to C group and DP group(P＜ 0.05). The expressions of PPAR-γ in hippocampuses and hypothalamuses of D group were significantly lower than C group and DP group(P ＜ 0.05). Conclusions Pioglitazone could increase the expressions of PPAR-γ in hippocampus and hypothalamus of diabetic rats， which may be related to the improvement of spatial learning and memory function caused by pioglitazone.