Current study dealt with the economical and environmentally friendly process of producing silver nanoparticles (AgNPs) through the use of an aqueous extract of ginger (Zingeber officinale) that is considered as ecofriendly and cheap method. The produced biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Fourier Transform Infra-Red spectroscopy (FTIR) and Zeta potential analysis. Then exhibited the antimicrobial activities of the biosynthesized silver nanoparticles against 30 clinically isolates of Multi Drug Resistant (MDR) bacteria which are Staphylococcus aureus (S.aureus), Pseudomonas spp., Klebsiella spp., Escherichia coli (E.coli) and Proteus spp. were carried out in Medical Microbiology and Immunology Department, Faculty of Medicine, Tanta University, after determined them by biochemical and antibiotic sensitivity tests. Then studied the effect of biosynthesized silver nanoparticles on the clinically isolated multi drug resistant bacteria by disc diffusion method. Additionally, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of biosynthesized AgNPs were estimated to be ranged from 31.25μg/ml to 250μg/ml    and from 125μg/ml to 500μg/ml, respectively of tested MDR strains. Furthermore, the effect of AgNPs on the ultrastructure and morphology of the bacterial cells (Proteus spp. and S.aureus) showed the cell membrane rupture leading to the death of the cells compared with the untreated bacterial cells which detected by Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM).