Background: Monosodium glutamate (MSG) is food additive, has effects on cerebellar cortex. It induces oxidative stress and decreases antioxidant capabilities. The health benefits of vitamin C are derived from its role in a number of key pathways within the immune system. Aim: This study aimed to evaluate the effect of MSG on the rat cerebellar cortex with the possible protective role of vitamin C. Material and Methods: Twenty-one new-born and twenty-one 20-day-old of suckling male albino rats were randomly divided into three groups in each age group. There were control groups (n=9); MSG-treated groups (n=6), in which the animals were treated with MSG 4 ‎ g/kg body weight ; and MSG + vitamin C treatment groups (n=6) , in which the animals were treated with MSG 4 ‎g/kg body weight and vitamin C 500 mg/kg orally. After ten days from the beginning of the experiment, the animals were anaesthetized by thiopental sodium. Cerebellar specimens were obtained, and then, processed for both light and electron microscopic examination. Results: MSG administration resulted degenerative changes of neurons, observed in the 10-day-old group, and Purkinje cell loss, in the 30-day-old group, Purkinje layer showed multiple focal areas of loss, dark irregular cells with marked ultrastructural abnormalities. GFAP showed good evidence of gliosis in the MSG-treated groups. Fortunately, co-administration of vitamin C reduced these effects. In conclusion, MSG has neurodegenerative effect on cerebellar cortex and vitamin C supplementation could protect from neurotoxic effect of MSG.