This paper presents the changes induced in the dielectric constant and structural properties of the poly vinyl chloride (PVC) sheets due to gamma radiation. PVC sheets were irradiated for different doses like 0 Mrad, 10 Mrad, 20Mrad, 30Mrad, 40Mrad, 50Mrad by Co60 source with a dose rate of 0.25 Mrad/hr at room temperature. FTIR spectra of the PVC samples before and after irradiation indicate that the gamma irradiation results in the formation of free radicals. In turn they bring in changes in the dielectric properties of PVC samples. It has also been observed that crystallinity of the sample changes due to gamma irradiation.