The paper provides an analysis of the current state of the quinoa seed market in the world and the prospects for its production in Ukraine. The main producers of quinoa are Peru, Bolivia and Ecuador. Due to its rich chemical composition, quinoa seeds are rapidly gaining popularity. Ukrainian enterprises use quinoa grain for the production of various products and semi-finished products. Quinoa seeds are attracting increasing attention worldwide not only for their nutritional and functional properties, but also for their ability to grow in adverse climatic conditions. Increasing demand and rising global prices for quinoa is encouraging producers to adapt the crop to low altitudes and grow it in arid conditions. Breeders and scientists of different countries are actively working on the adaptation of quinoa seeds to growing in different regions, which has an important impact on food security. Quinoa grain imported to Ukraine requires long-term storage without weight loss and quality deterioration. An important influence on the state of grain mass during storage is its hygroscopicity, that is, the ability to sorb and desorb water vapor. Knowledge about the hygroscopic properties of grain is of practical importance for the scientific justification of the choice of rational modes of storage and post-harvest processing. The main characteristic of the hygroscopic properties of grain materials is the equilibrium moisture content, therefore, its determination is an important step in preserving grain quality. The equilibrium moisture content of quinoa grain was determined. The research was carried out by the generally accepted tensimetric method in the range of air temperatures ±(5...25)°С and relative air humidity 40...80%, which simulate the conditions of grain storage and correspond to long-term average data, corresponding to warm and cold seasons in Ukraine. The nature of the change in the equilibrium moisture content of quinoa grain depending on the temperature and relative humidity of the air has been established. As the relative humidity increases and the ambient temperature decreases, the equilibrium moisture content of the quinoa grain increases. Empirical coefficients were determined and an equation was proposed that describes the dependence of the equilibrium moisture content of quinoa grain on the parameters of the surrounding air, which can be used to predict its change. The obtained data are of practical importance for the selection of high-quality storage regimes for quinoa seeds.