The increased incidence of inhalation exposure to manganese had resulted in increased attention to the potential toxic effects of manganese especially its adverse neurotixuc effects. The central nervous system represents an important target for manganese (Mn) intoxication that may cause neurological symptoms similar to Parkinson's disease in human. The aim of this work was to investigate the exposure response relationship of bioaccumulation, neurophathology and neurobehavioral damage following sub chronic inhalation exposure to Mn phosphate. For this purpose 45 Sprague-Dawley rats were divided into 3 groups (fifteen each), G1 were kept as a control, and G2 and G3 were exposed to managanese phosphate inhalation in a dose of 300 and 3000 microg/m3, 6 hours/day, 5 days/week, for 12 consecutive weeks. At the ends of the experimental period, rats were exanguinated, the brain of all rats were rapidly collected, weighted, and part was taken for determination of manganese level while the other part used for histopathological examination. There was a significant increase in manganese level in the blood and brain samples of the treated groups, this increase was dose dependant. While brain specimens showed focal glial cells proliferation, various degrees of neuronal degeneration, prominent astrocytic nodules. Our results reinforce the hypothesis of the neurotoxic effects of manganese after its sub chronic exposure and increased the attention of the dangerous effects resulted from the addition of MMT to unleaded gasoline.