TO evaluate the influence of cell type and cationic liposomal formulation on gene transfection efficiency three liposomes (lipofectin, lipofectamine and DOTAP) were used to transfect the human (A172 and MOG-GCCM) and rodent (C6 and A15A5) glioma cell lines with the Lac Z gene. Parallel studies evaluated in vitro cytotoxicity and the neuropathological changes following intracerebral injection. The transfection efficiency and cytotoxicity of the liposomes varied both quantitatively and qualitatively between the cell lines. There were no behavioural disturbances following intrastriatal or hippocampal injection and the neuropathological changes at the injection sites were focal and similar for all liposomes. The influence of glial cell lineage on both liposomal transfection facility and cytotoxicity may have important implications for in vivo gene transfection in the central nervous system.