The present aimed to clarify the different toxicological effects due to toluene exposure either through occupational contact or due to its abuse be “glue snuffers”. The study was conducted on 24 mature albino rats classified into two groups. The first group saved as control and the other group was kept in a closed chamber and exposed to toluene vapour “200 ppm” by static inhalation. The time of exposure was eight hours per day, five day per week and experiment extended for four weeks. Many clinical manifestations were observed. We studied the effect of toluene exposure on discriminative behavior as a measure of intelligence. Urine samples were collected in clean vials containing sodium azide as a preservative and kept frozen till chemical analysis for toluene metabolite (hippuric acid and ortho-cresol) using HPLC. At the end of the experiment, animals where sacrificed and the ration of brain/body weight was estimated. A portion of the brain was used for estimation of neurotransmitters contents (dopamine, norepinephrine and serotonin). Histopathology revealed congestion of blood vessels and desquamation of lining epithelium of the trachea and partial or complete occlusion of bronchi and bronchioles. Brain revealed severe congestion together with cerebral and cerebellar necrosis. Testes showed multinucleated giant cells with cellular debris in the lumen of seminiferous tubules. Liver showed hydropic degeneration. The kidneys showed cloudy swelling.