Nine kinds of nanostructured Cr2N/Cu multilayer thin films were deposited by the bipolar asymmetry reactive pulsed DC magnetron sputtering system. The antibacterial tests of coatings with various bilayer periods (Lambda) and different Cr2N/Cu thickness ratios were performed to evaluate the bactericidal ability by E. coli, S. aureus and P. aeruginosa, respectively. The Lambda value, thickness values of Cr2N to Cu layers significantly affected the bactericidal rates. The 100% bactericidal rates were achieved when the Lambda value reached 20 nm. For the same Lambda= 12 nm Cr2N/Cu multilayered coatings, the thickness ratio of Cr2N to Cu also showed strong influence on the bactericidal rates. (C) 2010 Elsevier B.V. All rights reserved.