To investigate the expression of Cdk5 and p35 in primary cultured astrocytes and the changes in expression induced by ischemia/reperfusion. Methods: Astrocytes were cultured from SD neonate rats. The expression and distribution of Cdk5 and p35 in cultured astrocytes were analyzed by immunofluorescence staining. Primary cultured astrocytes were subjected to oxygen-glucose deprivation/ reperfusion (OGD/R), and the changes in Cdk5 and p35 expression after OGD/R were observed by Western blot. Results: Cdk5 and p35 were expressed in astrocytes, mainly in the cytoplasm and less in the nucleus, and both displayed similar cellular distribution. The expression of Cdk5 and p35 in astrocytes was increased during early phases and decreased during late phases after OGD/R. Conclusion: Both Cdk5 and p35 were expressed in astrocytes, and both showed similar, mainly cytoplasmic distribution. Cdk5 and p35 expression in astrocytes exhibited dynamic changes after OGD/R.