The present study was aimed at investigating the toxic effect of copper on seed emergence, seedling growth, chlorophyll contents and copper concentration in different parts of soybean [Glycine max (L.) Merr.]. Four soybean cultivars viz Walliam82, NARC-2, Rawal-1 and Ajmeri-2104 were stressed with six Cu concentrations i.e., 50, 100, 150, 200, 250 and 300 mg Cu L-1 in two factor factorial completely randomized design with three replications. It was noted that shoot and root weights decreased gradually as the concentration of Cu increased for all cultivars especially Rawal-1 while Ajmeri-2014 was found as the most tolerant. Moreover, with the increase in the concentration of Cu, the drastic effect on growth and chlorophyll contents was recorded in Rawal-1 followed by NARC-2 > William-82 while Ajmeri-2014 showed tolerance under Cu toxic impacts. The addition of biogas slurry (BGS) improved plant growth, total chlorophyll contents and Cu concentration in soybean seedlings. Different levels of BGS (0, 2, 3, 4, and 5%) were applied but 4% significantly mitigated the adverse effect of Cu stress. It was concluded that Rawal-1 was more sensitive to Cu stress followed by Walliam-82, NARC-2 and Ajmeri-2104. Among all cultivars, Ajmeri-2014 is a suitable cultivar for Cu affected soils and BGS could be used an amendment under Cu contaminated soil to relieve the stress in soybean.