Black gram is one of the less‐known legumes, mainly grown and consumed in India, Thailand, and other tropical parts of the world. A field experiment was conducted during rainy seasons of 2014 and 2015 to study the Biochemical study on Phaseolus mungo L. The nutrient contents in grain and straw viz., N, P, K and S deviated significantly due to sulphur levels and bio fertilizers as well as their interactions. The highest sulphur level (60 kg/ha) and dual bio fertilizers (Rhizobium + PSB) resulted in almost significantly higher N, P, K and S contents and their uptake of black gram. The highest uptake of nutrients by black gram producing a total biomass up to 31.36 q/ha with highest S level was 99.55 kg N, 11.696 kg P, 52.06 kg K and 5.413 kg S/ha. Similarly, under dual bio fertilizers, the corresponding uptake values were 101.63 kg N, 10.626 kg P, 53.19 kg K and 5.568 kg S/ha. Biological nitrogen fixation by symbiotic bacteria in root-nodule of legume plants, black gram is one of them, is quantitatively one of the most important ways in which atmospheric nitrogen enters the biosphere.