Man-made environmental pollution, low iodine content in soils and waters leads to the spread of endemic goiter in animals and humans. The main sources of iodine in the body are food and drinking water, which determines the high dependence of the health of the population that consumes local food on the level of iodine in the soils and natural waters of agricultural landscapes. The article presents the results of cartographic analysis of thematic maps of Mongolia, medical data and data on the content of iodine in soils obtained from open sources. For the Ulaanbaatar region, the authors also used their own field and analytical data on the content of iodine in drinking water obtained in 2015-2017.the hypothesis about the influence of geographical and edaphic conditions on the causes of iodine deficiency in various parts of The country was tested. The average content of iodine in the soils of Mongolia ranged from 0.5 to 3 mg / kg, while the most iodine-deficient areas were identified for the southern and partially Eastern aimags (territories) of the country. The data obtained deserve attention and consideration when organizing the prevention of iodine deficiency in Mongolia.