A simple method for the rapid synthesis of selenium nanoparticles (SeNPs) by the reduction of selenium dioxide using an aqueous egg white lysozyme solution (stabilizing agent) and ascorbic acid solution (reducing agent) has been described. The formation of SeNPs is assured by characterization with UV-Vis, FT-IR, XRD and morphological characters that were observed using TEM analyses. The absorbance of the SeNPs is found at 250 nm. The TEM images show that the SeNPs are uniform and in spherical shape of size 40-60 nm. The crystalline nature of SeNPs is assured by XRD analysis. The antibacterial property of synthesized SeNPs was tested against the pathogenic bacteria, i.e., Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus pneumoniae, Proteus mirabilis and Klebsiella pneumoniae. SeNPs showed more antibacterial activity against B. subtilis (19 mm) and Streptococcus pneumoniae (15 mm) as compared with commercially available antibiotics such as streptomycin and erythromycin. The SeNPs synthesized via this process has proficient antimicrobial activity against pathogenic bacteria. SeNPs could play a significant role in pharmaceutical industries for the development of efficient antibiotic agents.