We quantified the number of glial fibrillary acidic protein immunoreactive (GFAP-IR) astrocytes in the CA1 and CA3 areas of the adult rat hippocampus. The dorsal and ventral regions of the hippocampus were taken into account to estimate the GFAP-IR cells using unbiased stereological techniques. Males had a higher number of GFAP-IR astrocytes in the CA3 area, whereas females had more in the CA1 area. No sex difference was found between dorsal and ventral regions, although most GFAP-IR astrocytes were located in the dorsal hippocampus.