TaN–Cu and TaN-Ag nanocomposite films were deposited by reactive co-sputtering on Si. The films were then annealed using RTA (Rapid Thermal Annealing) at 400 °C for 2, 4, 8, 15 minutes respectively to induce the nucleation and growth of metal particles in TaN matrix and on film surface. The samples were then tested for their anti-bacterial behaviors against Gram-negative and Gram-positive bacteria. The results were compared with the solubility of Ag and Cu in a buffer solution. Under similar ion concentrations, it is concluded that Ag ion or TaN-Ag is more effective against E. Coli (Gram-negative), while Cu ion or TaN-Cu is more effective against Staphylococcus aureus (Gram-positive).