Background: Immunohistochemical markers are considered as important factors in diagnosis of malignant astrocytomas. The aim of the current study was to investigate the frequency of the immunohistochemical markers neurofilament protein (NFP) and glial fibrillary acidic protein (GFAP) in malignant astrocytoma tumors in Firoozgar and Rasool-Akram hospitals from 2005 to 2010. Materials and Methods: In this cross-sectional study, immunohistochemical analysis of NFP and GFAP was performed on 79 tissue samples of patients with the diagnosis of anaplastic and glioblastoma multiform (GBM) astrocytomas. Results: The obtained results demonstrated that all patients were positive for GFAP and only 3.8% were positive for NFP. There was no significant association between these markers and clinical, demographic, and prognostic features of patients (p>0.05). Conclusions: NFP was expressed only in GBMs and not in anaplastic astrocytomas. It would be crucial to confirm the present findings in a larger number of tumors, especially in high grade gliomas.