The γ-ray irradiation effects on fluorozirconate glass have been studied by means of Electron Spin Resonance spectroscopy (ESR) at liquid-nitrogen temperature and room temperature. The irradiationinducod defects were found to be Zr3+, F0, F2- and a kind of centers assigned as a hole trapped on oxygen impurity (U signal). The presence of non-bridging fluorines is tho reason to cause the defects F0 and F2-, when the irradiation is performed at low temperatures. These defects are unstable, at about 400 K all defects vanish from ESR spectra of this glass. The γ-ray irradiation at room temperature produces a absorption peak within ultraviolet region and almost has no effects on the transmission within infrared region.