Fas/APO-1 (CD95) is a cell surface receptor that mediates apoptosis when it reacts with Fee ligand (FasL) or Fas antibody. We previously reported that Fas expression is predominantly induced in perinecrotic glioma cells, suggesting that Fas induction is associated with epoptosis and necrosis formation, a histological hallmark of glioblastomas. In this study, we assessed the expression of FasL in 10 glioblastoma cell lines and in 14 astrocytic brain tumors (three low-grade astrocytomas and 11 glioblastomas). Reverse transcriptase (RT)-PCR revealed that all glioblastoma cell lines and primary astrocytic brain tumors express FasL. Immunohistochemically, feel was predominantly expressed on the plasma membrane of glioma cells. These results suggest that FasL expression is common in human astrocytic brain tumors and may cause apoptosis of glioma cells if Fee expression is induced.