ABSTRACT The continuation emergence of multidrug resistant bacterial infections and the decline in discovery of new antibiotics are main challenges for health care throughout the world. Recently, chemically and biologically synthesis nanoparticles are used as new antimicrobial agents. Present study focused on detection antimicrobial action of biosynthesis nanoparticles versus chemically synthesis nanoparticles on bacterial infections in Lab. Method: in this study, zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs) are produced from zinc nitrate and silver nitrate respectively by chemical and biological methods. One concentrations of metallic nanoparticles (60ppm) are tested against salmonella typhi (S. typhi), Pseudomonas aeruginosa (P. aeruginosa), Streptococcus pneumonia (S. pneumonia) and Streptococcus aureus (S. aureus) by disc diffusion method. Result: biologically synthesis AgNPs more effected on bacterial species (especially on S. pneumonia) than biologically synthesis ZnONPs, chemically synthesis ZnONPs and chemically synthesis AgNPs. On other hand biologically synthesis ZnONPs more effected than chemically synthesis ZnONPs on bacterial species especially S. pneumonia. Conclusion: biologically synthesis nanoparticles more effected on tested bacterial species especially S. pneumonia then chemically synthesis nanoparticles. Biologically synthesis AgNPs are an excellent antimicrobial agent.