Doxycycline (Doxy) is a tetracycline antibiotic with a potent antibacterial activity against a broad range of bacteria. Using nanotechnology is one feasible way to increase the antibiotics' ability to penetrate the body and increase their antibacterial effectiveness. In this work, we report the formation of a stable green synthesized silver nanoparticles (AgNPs) by chitosan with Doxy nanocomposite for the first time. The obtained nanoparticles were characterized by transmission electron microscopy (TEM), zeta-potential, UV-Visible spectroscopy and four transform infrared spectroscopy (FTIRs). The antibacterial effect of doxy, AgNPs and doxy/AgNPs were determined on Gram-positive Staphylococcus aureus, Streptococcus mutans and Gram-negative Escherichia coli, Klebsiella pneumonia. This combined therapeutic agent restored the susceptibility of doxy and showed an antibacterial activity against tested bacteria. AgNPs has absorption peak at 445 nm, mixing of Doxy with AgNPs causes all doxy absorptions to red shift and a broadening in surface plasmon resonance (SPR) for AgNPs and show a slight increase in particle size of AgNPs from 12 ± 2 nm to 14 ± 2 nm with high stability as zeta potential was 29 mv and 48.5mv for AgNPs and Doxy/AgNPs respectively. The antibacterial effect of Doxy/AgNPs nanocomposite was found to be twice effect of free doxy, suggesting a synergistic interaction between the two components. In conclusion, synergy of doxy with AgNPs is quite promising for antibiotic resistant strains. These results highlight the ability of AgNPs to boost the efficacy of the doxycycline.