The article presents studies on the effect of biopreparations on nitrogen assimilation in spring soft wheat plants grown under stressful conditions resulting from either water deficit or excess soil moisture. It is known that recent years have seen a tendency towards an increase in the area of arable land in the Russian Federation affected by droughts, as well as periodic flooding and waterlogging, which significantly damage agricultural production. In this regard, the search for strategies to mitigate the negative effects of stress responses induced by either water deficit or waterlogging is of great practical and environmental significance and remains highly relevant. The aim of the study was to investigate the effect of biopreparations on nitrogen assimilation in two different spring wheat varieties under simulated water supply stress conditions. Spring wheat plants of the varieties Zlata and Radmira were grown under controlled vegetation conditions using a modified soil culture technique. The soil used was typical light loamy urbanozem, collected from the field experimental station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. An adaptive effect of biopreparations was established under water deficit conditions, influencing nitrogen uptake by plants and the extent of nitrogen assimilation in wheat grain, thereby enhancing the ability of spring soft wheat to withstand adverse environmental conditions. A positive effect of the studied preparations on nitrogen uptake and assimilation processes in spring soft wheat plants varieties Zlata and Radmira was revealed. The effectiveness of biopreparations under various water supply stress conditions depended on their chemical composition and application method. It was shown that the greatest adaptive capacity of biopreparations was manifested under drought conditions during the critical period of plant development in both wheat varieties. The application of biopreparations provided optimal conditions for nitrogen uptake by plants and enhanced nitrogen assimilation processes, thereby promoting adaptive responses in plants and increasing the ability of spring wheat to withstand adverse environmental conditions.