Abstract: Staphylococcus aureus is a leading cause of nosocomial infections and the etiologic agent of a wide range of diseases associated with significant morbidity and mortality. Some of the diseases mediated by this species include endocarditis, osteomyelitis, toxic shock syndrome, food poisoning, and skin infections. Biofilms are well organized and complex aggregate of microorganisms, surrounded by a protective matrix of exo-polysaccharides and can adhere to each other on various surfaces. Because of increase the drug resistance and the side effect of over use of antibiotic, it is necessary to find a suitable agent to reduce the growth of microorganism. Biofilm are known as a significant problem because biofilm formation protects pathogenic bacteria against antibiotics and is one of the main causes of development of chronic infections. Thus biofilm is the main cause of drug resistance in microbial strains. These strains cause pathogenicity to a maximum extent and thus cause resistance against the conventional antibiotics/drugs. Silver is known as an antimicrobial agent and is utilized in several antimicrobials and medications. Staphylococcus aureus strains were isolated and screened for biofilm production. In the present investigation, the nano-particles were prepared of Ag+. The biosynthesized silver nanoparticles (AgNPs) were characterized by UV-Vis spectroscopy and Transmission electron microscopy (TEM). UV-Vis spectra of silver nano-particles showed absorption spectra at 450 nm corresponding to the surface plasmon resonance of silver nanoparticles. The size and morphology of the fused nanoparticles were determined by TEM, which shows the formation of spherical nanoparticles in the size range of 5-20 nm. The antibacterial activity of biosynthesized AgNPs, were evaluated by measuring the diameter of zone of inhibition against pathogenic microbial strains and drug resistant Staphylococcus aureus.