Background: Water is an essential solvent and used daily by humans. Consumption of water contaminated with diesel has been shown to impact negatively on organs such as the brain, liver, spinal cord, kidney and others. The brain is a prime organ in the human body and responsible for general coordination and intelligence. Protecting the brain from harmful substances is necessary as this would mitigate neurodegenerative disorders which are obvious in our society. This study was carried out to determine the possible effects of diesel fuel on the histology of the brain of male albino wistar rate. Materials and Methods: A total of 20 rates were used to carry out this research. The animals were grouped in 2 groups; groups A (Control) and B. Group A was administered with good feed and clean water. Group B was administered with feed and water contaminated with diesel for varying periods of time ranging from 1 to 5 weeks. At the end of the given periods the brains were harvested and histopathological investigations for alteration in brain tissues was carried out using routine tissue processing methods and H and E staining methods. Results and Discussion: There was no histopathological alteration of brian tissues harvested from the control animals which were administered with clean water and uncontaminated feed. There was no alteration of brain tissues observed after week 2. The brain tissues harvested from animals whose feed and water were contaminated with diesel showed no histopathological changes when compared with that of the control (group A). A similar observation was made for weeks 3 through 5 for the animals in group B. Conclusion: There were no observed effects of diesel contaminated water on the histology of the brain tissues of male albino wistar rats which may be due to the active protecting effect of the blood-brain barrier