Silver nanoparticles in the range of 10–40 nm were synthesized chemically and by laser ablation, employed for in vitro antibacterial action against human pathogenic bacterium. Their formation was evidenced by UV-visible spectrophotometer; particle size confirmed by atomic force microscopy, crystal structure determined by X-ray diffraction and chemical composition investigated by Fourier transform infrared spectroscopy. The calculated MIC(minimum inhibitory concentration) of chemically synthesized nanoparticles with 30–40 nm in size are 2.8 μg/m L, 4.37 μg/m L, 13.5 μg/m L and 2.81 μg/m L for E. coli, S. aureus, B. subtillis and Salmonella, respectively. Whereas laser ablated nanoparticles exhibit MIC of 2.10 μg/m L, 2.36 μg/m L and 2.68 μg/m L for E. coli, S. aureus and Salmonella, respectively. Silver nanoparticles in the range of 10-40 nm were synthesized chemically and by laser ablation, employed for in vitro antibacterial action against human pathogenic bacterium. Their formation was evidenced by UV-visible spectrophotometer; particle size confirmed by atomic force microscopy, crystal structure determined by X-ray diffraction and chemical composition investigated by Fourier transform infrared spectroscopy. The calculated MIC (minimum inhibitory concentration) of glycoprotein nanoparticles with 30-40 nm in size are 2.8 μg / m L, 4.37 μg / m L, 13.5 μg / mL and 2.81 μg / mL for E. coli, S. aureus, B. subtillis and Salmonella, respectively. Whereas laser ablated nanoparticles exhibit MIC of 2.10 μg / mL, 2.36 μg / mL and 2.68 μg / mL for E. coli, S. aureus and Salmonella, respectively.