Introduction: Hippocampus is the part of the brain responsible for long term memory and emotions and it needs insulin for its unhindered function. Insulin, together with leptin, regulates the energy metabolism of the organism. Its activity is realized through receptors that have been shown to be located in the peripheral lipid rafts, highly regulated membrane domains, whose main organizers are gangliosides. Goals: To determine the expression of insulin receptor in hippocampus of the genetically modified B4Galnt1 mouse with disorder in the synthesis of the complex gangliosides. Materials and methods: Wild type mice (WT) and genetically modified mice (KO) were included in the research. First, the genotype was determined, then the animals were sacrificed, and the brains were isolated, fixed and cryoprotected. In order to determine the distribution of the α-subunit insulin receptor, immunohistochemical analysis of hippocampus tissue was performed using high-specific anti-IR-α on 35 μm thick cryostat cuts by free-floating cuts method. The results were analyzed using a light microscope and were photographed by camera. The created images were analyzed in Fiji and the statistics were made in the Statistics 12 program. Results: The highest expression of IR-α was observed in the CA3 area of the hippocampus of both investigated mice. In a genetically modified mouse, the distribution was reduced in all three domains in relation to the control mouse. The difference in CA3 and DG area is statistically significant while the difference in CA1 exists but is not statistically significant. Conclusion: Complex gangliosides play an important role in the formation of the lipid environment of the insulin receptor in the hippocampus. Using the genetically modified mouse B4Galnt1 with a disorder in the synthesis of complex gangliosides has shown that expression of the insulin receptor decreases.