Copper oxide nanoparticles (CuONPs) were prepared using ecofriendly simple method that employs the extract of Syzygium Aromaticum (clove buds) as a reducing and stabilizing agent. The prepared CuONPs were characterized by FT-IR, SEM and EDS techniques to study their morphological and compositional properties. Fourier transform infrared spectroscopy (FTIR) analysis shows the presence of different functional groups at various positions. Morphological studies were used to study the shape and size of the synthesized nanoparticles. Energy dispersive spectroscopy (EDx) attests the high intense metallic peak of copper (Cu) and low intense peaks of carbon (C), oxygen (O), chlorine (Cl) and phosphorus (P) elements due to the capping action of biomolecules of bud extract in used in CuONPs formation. The antibacterial activity of the synthesized CuONPs against gram – ve microorganisms viz. E-Coli, Salmonella and Enterobacter bacteria was studied. The produced CuONPs show resistance to the three types of bacteria with greatest resistance to E-Coli followed by Salmonella and then Enterobacter.