This study aimed to assess the effect of drought stress on some morphological, physiological, and biochemical parameters in soybeans. The study investigated the water exchange indicators of seven soybean (Glycine max L.) varieties - Arisoy, Zara, Zamin, Chara, Olmos, Bars, and Optima - under different soil moisture conditions (70%, 50%, and 30% of total field capacity) in the meadow-alluvial soils of the Bukhara region. Field experiments were conducted to evaluate diurnal leaf water deficit using physiological measurements at various growth stages (budding, flowering, and pod formation). The results showed significant varietal differences in leaf water deficit depending on soil moisture and phenological phases. The highest deficit was recorded in Bars, Optima, and Zara varieties under 30% moisture, while Arisoy and Zamin maintained lower values, indicating better drought tolerance. Overall, decreased soil moisture increased water deficit across all varieties.