The majority of chemicals present in the environment have not received adequate testing to determine their neurotoxic potential. Thus, the US EPA has prepared guidelines for neurotoxicity testing for both new and existing chemicals. Based on these guidelines, a core battery of tests to assess the behavioral and neurological integrity of laboratory rats was developed for use in the primary screening of chemicals. The study systematically applies the FOB and MA to characterize known neurotoxicants and to assess sensitivity, reliability, selectivity, and specificity of the tests. The FOB includes home-cage and open-field observations, and neuromuscular, sensorimotor, and physiological measures. MA is measured in an automated photocell device (figure-eight maze). The tests have been demonstrated to be sensitive to a variety of neurotoxicants, and profiles of effects can be established to distinguish between them. The data provide important information on the feasibility and interpretation of functional evaluations in the hazard identification of neurotoxic chemicals.