In the last decades of the twentieth century, in the national economy of many countries, organochlorine pesticides were most widely used, characterized by stability in the external environment, the ability to cumulate in various tissues of organisms. Lindane (the gamma isomer of hexachlorocyclohexane) is listed as a restricted persistent organic pollutant and is an ecotoxic substance with severe and chronic effects on the human body. The study of the effect of lindane on carbohydrate metabolism at the present stage is still insufficient. This fact led to the study of the effect of γ-HCH on the insulinogenic function of the pancreas in in vivo and in vitro experiments. In experiments in vivo, the animals of the experimental groups were once orally administered γ-HCH at a dose equal to 1/5 DL50. Isolated pancreatic islets, precipitated in vitro and fixed on mica plates, were exposed to γ-HCH in amounts equivalent to 1/5 to 1/4 DL50. Paraffin sections of pancreatic tissue from experimental and control animals were stained with aldehyde fuchsin according to Gomori, and tissue preparations were also examined by a highly specific method for detecting insulin in β-cells using diethylpseudoisocyanin staining, followed by examination of the preparations in the ultraviolet light of a luminescent microscope.The same methods were used to study preparations of isolated pancreatic islet tissue on the 4th day of cultivation. The influence of orally administered γ-HCH on the level of immunoreactive insulin in the blood of experimental animals was also studied. The insulin level was determined by the enzymatic-immunological method. The concentration of IRI was established before the start of the experiment and 4-4.5 hours after acute inoculation. Results and their significance. In the study of stained preparations of the pancreas of experimental animals, numerous islets of ordinary sizes were revealed, the cytoplasm of which was filled with aldehyde-fuccin granularity in quantities indistinguishable from those observed by microscopy of preparations of control animals. The value of the fluorescence coefficient in the histofluorimetric study of the control and experimental preparations did not differ significantly. However, the content of IRI in the blood serum showed a distinct decrease in the first hours after priming. In experiments in vitro, when studying the effect of γ-HCH on cultured tissue, introduced into the nutrient medium on the second day, in the field of view of the microscope, single, small pancreatic islets were revealed. Their number on a constant area of the plates was significantly lower than the value of the same indicator in the study of control preparations. Thus it has been shown that γ-HCH does not affect the histostructure of the endocrine pancreas, but causes a significant decrease in IRI in the blood serum, as well as a change in the histochemical characteristics of cultured β-cells.