Abstract:The use of Rhodopseudomonas palustris in biosynthesis of silver nanoparticles (AgNPs) emerges as a reliable and eco-friendly approach in recent years. This report focuses on extracellular biosynthesis of AgNPs using cell filtrate of Rhodopseudomonas palustris. These nanoparticles were characterized by UV-vis spectrum, X-ray diffraction (XRD) spectrum and transmission electron microscopy (TEM). UV-vis spectrum of the aqueous medium containing silver ion showed a peak between 420 nm?460 nm corresponding to the plasmon absorbance of AgNPs. TEM micrograph showed formation of the AgNPs in the range of 5 nm?20 nm. XRD of the nanoparticles confirmed the formation of metallic silver. The AgNPs were evaluated for their antimicrobial activities against Escherichia coli and Staphyloccocus aureus.