Abstract: Microbial biofilms, which are formed when bacterial and/or yeast cells adhere to abiotic and biotic surfaces represent the most prevalent type of virulent factor involved in the crucialdevelopment of clinical infection exhibiting resistance to antimicrobial agents. Metalnanotechnology chemistry has the potential to prevent the formation of these life-threatening biofilms on life supporting devices. The present study is undertaken to evaluate the antibiofilm effect of metallic silver nanoparticles (AgNP) stabilized with biocompatible chitosan polymer against biofilm of clinical isolate of Escherichia coli and their effect on biochemical composition of biofilm matrix in terms of total carbohydrate and total protein under in vitro condition. Free and chitosan stabilized AgNPs were characterized by Fourier Transform Infrared Spectroscopy(FTIR), Transmission Electeron Microscopy (TEM), Scanning Electron Microscopy (SEM) and EDS (Energy Dispersive Spectroscopy). Both free as well as the stabilized nanoparticles were found to be effective in bringing about the inhibition of biofilm formation. But enhanced biofilm inhibitory effect inhibition was observed in case of polymer stabilized nanoparticles. Biochemical composition of biofilm matrix in terms of total carbohydrates and total proteins was appreciably reduced in all tested concentration of polymer stabilized nanoparticles compared to free AgNPs.