Exposure of the developing or mature nervous system to neurotoxic xenobiotics results in complex behavioral, physiological and morphological alterations. With few exceptions, a biochemical basis for these toxicant-induced changes has yet to be described (Damstra and Bondy, 1982). The report briefly addresses the issues to be considered when developing a biochemical approach to neurotoxicity assessment and it reviews the progress of work concerning one strategy: the use of neurotypic and gliotypic proteins as biochemical indicators of neurotoxicity.