The present study analyzed the combined immunostaining for proliferating cell nuclear antigen (PCNA) and epidermal growth factor receptor (EGFR) with the aim of obtaining an objective method for the evaluation of the growth fraction in human glial tumors. A retrospective study was undertaken on 157 gliomas employing MoAb PC10 and MoAb 108, recognizing a 36 Kd nuclear protein associated with the cell cycle and the extracellular domain of the EGFR, respectively. The results of this immunohistochemical analysis showed that the rate of PCNA positive cell is directly associated to EGFR expression and significantly (P < 0.0001) correlates with tumor morphological grading, this was also the case in patients submitted to multiple surgical treatments for recurrent tumors. PCNA and/or EGFR are expressed by a minority of low grade astrocytoma, while anaplastic astrocytoma and glioblastoma displayed an intense immunoreactivity for the two antigens in more than 85% of tested cases. These findings indicate that the combined evaluation of PCNA and EGFR could allow a more definite biopathological grading of neuroepithelial brain tumours.