Biogenic method of synthesis of nanoparticles is being preferred over the conventional chemical and physical methods due to its reduced toxicity towards the environment which uses living organisms like plants, microalgae and other microorganisms. The biomolecules present help in the reduction of Sodium Selenite to its elemental form Selenium nanoparticles. Z. officinale was used for the synthesis of selenium nanoparticles which was confirmed by the color change from pale yellow to red. The morphology of the nanoparticles was characterized by various techniques like SEM, TEM, DLS and AFM which revealed the size of the nanoparticles to be around 100-150 nm with a spherical shape, while the Zeta potential results also revealed its high stability nature. Its anti-microbial activity was tested against five bacterial species Escherichia coli, Klebsiella sp., Pseudomonas sp., Staphylococcus aureus and Proteus sp. The antibacterial activity of selenium nanoparticles was found to be significantly effective against Proteus sp. when compared with other species and thus the growth curve of Proteus sp. bacterial isolate treated with SeNPs was estimated. The Minimum Inhibitory Concentration of the Selenium nanoparticles against Proteus sp. showed that a concentration of about 250 μg/mL was required to establish its bactericidal activity. The antioxidant activity was also checked by using the DPPH assay. In the need of developing an eco-friendly, cost-effective and efficient biomedical agent that can also be compatible with pharmaceutical and industrial purposes was served through this paper. © 2018