BACKGROUND: The study's main aim was to synthesize copper nanoparticles utilizing the aqueous extract of Suaeda monoica plant (Salt marsh), a mangrove plant. The nanoparticles synthesized are of small size and high stability, leading to further analysis of the antibacterial activity of gram-positive (S.mutans) and gram-negativeKlebsiella species, Salmonella typhi) bacterial strain using the disk diffusion method. The study is done to analyze the antibacterial activity of the biologically synthesized copper nanoparticles against various pathogenic bacteria.