Increase in interaction through the mobile phone may have adverse effects on the brain, especially on the hippocampus. so the radiation emitted from the mobile phone and its adverse effects is a serious concern in the society. In this study we have focused on the effects of chronic exposure to Mobile phone Radio Frequency–Elecro Magnetic Radiation (MP RF–EMR) on hippocampal CA3 neurons in swiss albino mice were investigated. 18 Swiss albino mice were divided into 3 Groups (Control, 30 Mins exp/3 Months & 60 Mins exp/3 Months). After the exposure the mice were euthanized, perfused transcardially, brains were extracted out and processed for histological procedures. Cresyl Violet stained hippocampal CA3 Pyramidal neurons shows more number of viable neurons which is healthy, compactly arranged with clear nucleus in control group, where as radiation exposed group neurons shows darkly stained, unhealthy, scattered and irregular with less number of viable neurons. The findings indicate that chronic exposure to mobile radiation leads to change in structural integrity of hippocampus also alter the cognitive function like learning and memory.