Introduction: It was aimed to investigate the effect of chronic toluene exposure on amino acid neurotransmitters in the rat brain, corpus striatum. METHODS: Twenty four male Sprague-Dawley rats were divided into one of three groups, control, acute, and chronic. Each groups was for the microdialysis to estimate the changes of amino acid neurotransmitters, aspartate, glutamate, and citrulline before, during, and after 3,000 ppm toluene exposure for 2 hours. RESULTS: The results were as follows; 1) Aspartate and glutamate concentration were generally decreased in the toluene inhalation groups compared with the control group and more significantly decreased in chronic inhalation group than other groups. 2) Citrulline that expressed the activity of nitric oxide synthase and taurine as an inhibitory amino acid showed no significant differences between all groups. Based on these results, it is suggested that the decreasing excitatory amino acids, aspartate and glutamate, are partly contributed to the toxic mechanisms of toluene in rat brain.