Little information exists about the possible neurotoxicity of styrene. The present study was designed to explore whether long term inhalation exposure (three months) to styrene (90 and 320 ppm) could induce long lasting astroglial alterations in Sprague Dawley rats, traceable four months after exposure ceased. Styrene exposure at 320 ppm induced such alterations as shown by raised concentrations of the glial cell marker, glial fibrillary acidic protein (GFA) in the sensory motor cortex and in the hippocampus. GFA is the structural protein of the astroglial filaments and formation of these filaments has been shown after damage to the central nervous system from any cause. It is concluded that exposure to styrene at moderate exposure levels induces regional, long lasting astroglial reactions that serve as an indicator of solvent induced brain damage.