Green biosynthesis of selenium nanoparticles (SeNPs) using Bacillus tropicus Ism 2 (MK332444) isolated from soil polluted with industrial wastewater near the Ismailia Canal, Egypt, was carried out. SeNPs were biogenically synthesized using bacterial pellets mixed with 1 mM Na₂SeO₃. Characterization of biosynthesized SeNPs was carried out by UV-Vis spectrum where SeNPs solution exhibited characteristic peak at 270 nm. Dynamic Light Scattering (DLS) analysis and High-Resolution Transmission Electron Microscope (HRTEM) showed spherical shaped SeNPs with size ranged from 60 to 125 nm with PDI= 0.544 and zeta potential value of -30.6. Biologically synthesized SeNPs showed no antibacterial activity against both Gram-positive and Gram-negative bacteria. Cytotoxicity of SeNPs was studied against Huh-7 human liver cell line and showed low cytotoxicity with IC₅₀ value of367±5.5 μg/ml. In conclusion in this work Bacillus tropicus Ism 2 locally isolated bacterium showed the capability to biosynthesize SeNPs with spherical shape and low cytotoxicity.