We report the conducting and transparent CdS films fabricated by the chemical spray pyrolysis technique (CSPT). The effect of gamma irradiation on the optical properties and dispersion parameters has been studied. The samples were subjected to a session of irradiation with gamma ray form Cs-137 (0.5 µCi) for 5 days. Optical absorption measurements were also studied by UV-VIS technique in the wavelength ranges 300-900 nm. The fundamental and onset energy gap amount for unirradiated and irradiatedCdS filmswere 2.43±0.01 eV and 2.41±0.01 eV respectively. The changes in dispersion parameters and Urbach tails were investigated. A slight decrease in the average oscillator strength was obtained after irradiation. The singleÂoscillator parameters were determined.