Zirconium oxide (ZrO2) films have been prepared by rf reactive magnetron sputtering at different sputtering pressures. It is found that the monoclinic phase is the dominant phase in the films and there is a small fraction of tetragonal phase in the films prepared in the low pressure region. The influence of sputtering pressure on the microstructure. residual stress and optical properties of the films has been studied. The films have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM). energy dispersive X-ray (EDX) and optical spectroscopy.