Effects of silver nanoparticles (Ag NPs) exposure on two geographical cultivars of Vigna subterranea were investigated. After inoculation in half strength Hoagland medium amended with Ag NPs for 15 days, both physiological and biochemical responses were evaluated. Exposure significantly decreased plant growth by up to 85%. Interestingly, Ag NPs exposure significantly decreased mean shoot biomass in all treatments but increased root mass (34% and 66%) in relation to control. Chlorophyll production was reduced by approximately 46% (in the more tolerant) and 86% (in the more sensitive) for the two cultivars and observed catalase activity was about 50% of the activity in NPs stressed root tissues for the sensitive cultivar. It may be perceived that the inherent stress is associated with observed surge in catalase activity across all cultivars. Also, the observed increase in catalase activity is positively correlated at 99.9% level (r=0.9571, n=10) with decreasing chlorophyll content on exposure. Recorded ascorbate peroxidase activity was higher in leaf tissues. Statistical analysis revealed marked difference between superoxide dismutase activities of V. subterranea cultivars and also between treatments. Time trend of transpiration rate revealed a decreasing order throughout growth period.