The use of microorganisms in the synthesis of nanoparticles emerges as an eco-friendly and exciting approach. In the present study, we report the biosynthesis of silver nanoparticles employing the bacterium E.Coli. The test bacterium was isolated from urine sample grown on EMB Agar medium and identified as E.coli bacteria. Synthesized nanoparticles were characterized by UV-Vis spectroscopy and the maximum absorbance was found to be around 400 nm. The particle size and lattice image of silver nanoparticles was studied by Transmission Electron Microscopy (TEM). The antibacterial activity of these nanoparticles was studied against bacteria Bacillus subtilis and Klebsiella pneumonia. Growth curves of microbes in presence of silver nanoparticles showed inhibition of growth suggesting antibacterial property of the silver nanoparticles.