The rapid growth in global population continues to challenge the world’s ability to provide enough food. As one of the most crucial issues for human development, food production must increase to offset hunger and poverty as well as social unrest. To augment the yield of crops a variety of pesticides like Endosulfan, Rogor, Aldrin, Chlorpyrifos, etc. are being used liberally by the farmers. In the present investigation, Endosulfan was administered orally (daily) by gavage method to female Swiss albino mice group for 4 weeks @ 3.0 mg/kg b.w. After that, they were left for 6 months and then sacrificed and liver tissues were fixed for light microscopy and Transmission Electron Microscopic study. The histopathological study of Endosulfan administered group liver showed hepatocytes with congestion in central vein with less dense cytoplasm, haemorrhaged bile duct, degenerated cytoplasm and central vein with vacuolations in sinusoidal spaces. Neoplastic changes in hepatocytes are the major finding of study. The ultrastuctural study revealed dilation in the nuclear pore complex and massive movement of cytoplasmic material from cytoplasm to the nucleus which is major finding which denotes neoplastic changes. Presence of abundant free lying polyribosomes in the cytoplasm, which denotes neoplastic changes in the cellis also one of theimportant finding observed. The present study thus deciphers that Endosulfan toxicity leads to onset of neoplasia thence carcinogenesis in liver cells in Swiss albino mice which is the novel finding in the field of toxicology.