Introduction Arsenic is a common environmental contaminant that is available worldwide. It has been reported that human arsenic exposure causes nervous system disturbances such as polyneuropathy and neurobehavioral deficits. Aim of the work The purpose of this work was to describe the histological changes induced by arsenic in the cerebral cortex of adult male albino rats and discuss its possible mechanisms of action. Materials and methods Twenty adult male albino rats were equally classified into control (I) and experimental (II) groups of 10 animals each. Rats of group II were intraperitoneally injected with 2mg/kg/day of sodium arsenite for 20 days. Samples from the temporal lobes of the cerebrum were taken and processed for light and electron microscopic examination. Results Features of neurodegeneration such as shrunken, irregular, and darkly stained nuclei and degenerating organelles were observed in arsenic-treated rats. Good evidence of gliosis and disrupted blood–brain barrier were also detected.