Male, albino rats of the Fisher strain were exposed to 2 mg carbon disulfide/l of air for 4 hours per day, 5 days per week for 6 weeks. Neurobehavioral effects were not observed after 3 weeks of dosing, but hindlimb extensor responses and performance on the inclined screen (motor coordination) were impaired after 6 weeks of exposure. Forelimb grip strength and exploratory locomotor activity were not affected. Three weeks after cessation of dosing, recovery of function was observed. Rats exposed to CS2 for 6 weeks were found to be stimulated less than air ventilated controls by 3 mg/kg of d-amphetamine. In addition, d-amphetamine-induced augmentation of an acoustic startle response was attenuated in CS2 exposed rats. These data suggest that repeated exposure to CS2 affects the availability of brain norepinephrine for release. Enhanced responsiveness to the stereotypic effects of a high dose of d-amphetamine (6 mg/kg) suggested changes in functioning of dopaminergic systems. Three weeks after cessation of dosing, there was no difference between groups in their response to d-amphetamine.