A field experiment was conducted for two consecutive years (during Kharif 2019 and 2020) at Instructional Farm, College of Agriculture, Jodhpur (Rajasthan) to assess the impact of varying levels of FYM, phosphorus and bio-inoculants on biological properties of soil under Mungbean. The experiment was laid out in factorial randomized block design with three replications. The experiment comprised of two levels of FYM (0 and 5 t/ha), four levels of phosphorus (0, 50, 75 and 100% P2O5 /ha) and three levels of bio-inoculations (No inoculation, Enterobacter cloacae and Bacillus amyloliquefaciens). Mungbean variety GM-4 was used for exprimentation. The results revealed that addition of FYM @ 5 t ha-1 recorded significantly higher soil microbial biomass carbon (217.92 mg /kg), soil microbial biomass phosphorus (15.47 mg/kg), acid phosphatase (1.019 \(\mu\)g PNP/g soil/h), alkaline phosphatase (7.13\(\mu\)g PNP/g soil/h) and dehydrogenase activity (6.10 \(\mu\)g TPF/g soil/ h) of soil at 40 DAS as compared to without FYM application. Among the phosphorus levels, application of 100% P2O5 /ha gave significantly highest soil microbial biomass carbon (219.13mg/kg), soil microbial biomass phosphorus (15.71 mg/kg), acid phosphatase (1.010 µg PNP/g soil/h), alkaline phosphatase (7.21\(\mu\)g PNP/g soil/h) and dehydrogenase activity (5.91\(\mu\)g TPF/g soil/h) over rest of P levels, however, it was found at par with 75 % P2O5 /ha. Similarly, the seed inoculation with B. amyloliquefaciens recorded significantly higher values of all above biological properties as compared to un-inoculated control but it was found at par with seed inoculation with E. cloacae. Thus, the results reaveal the positive effect of the application of FYM, Phosphorus and seed inoculation with biofertilizers (E. cloacae or B. amyloliquefaciens) on the biological properties of soil (soil microbial biomass carbon, soil microbial biomass phosphorus, acid phosphatase, alkaline phosphatase and dehydrogenase activity) for management of sustainable environment.