Objective To investigate the expression characteristics of the phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) in the central nervous system(CNS) of adult rats. Methods Immunohistochemical staining was used to demonstrate the PTEN-like positive immunohistochemical product. Results Expression of PTEN was extensive in the CNS. The distribution of positive cells was strong, moderate or weak and its subcellular localization included the cytoplasm, nuclei and processes. Conclusion The present results identify the expression of PTEN protein in the CNS of adult rats.