Thin films of zirconium dioxide have been deposited onto glass and silicon substrates using filtered cathodic vacuum arc deposition under a pulsed negative DC bias. The properties of the films have been investigated using X-ray diffraction, X-ray photoelectron spectroscopy, microhardness testing and optical analysis. It was found that the crystalline phase of the films was strongly influenced by the applied bias and that an amorphous-monoclinic transition occurred on glass substrates for bias values >250 V. The changes in crystallinity also resulted in an increase in the optical refractive index from 2.09 to 2.22 at 550 nm. A similar behaviour in the variation of the microhardness with applied pulsed DC bias was also observed, where the hardness increased from 11 GPa to 16. 5 GPa. Crown Copyright (c) 2010 Published by Elsevier B.V. All rights reserved.