In this work, cellulose nitrate films were irradiated with different doses of gamma irradiations. The gamma irradiation doses were 25, 55, 120, and 170 kGy. The compositional transformation, optical properties, and morphological changes resulted from the gamma irradiation were obtained using different spectroscopic methods. These methods were Fourier transform infrared spectrometry, UV/visible spectrometry, and scanning electron microscope. The surface roughness, as well, for pristine and gamma-irradiated polymer films was determined. The obtained results exhibit changes in the absorbance intensities of the function groups of the irradiated cellulose nitrate films. An induced increase in the UV/visible absorption spectra with increase in the gamma irradiation was observed. A noticeable shifting in the UV/visible spectra toward higher wavelength and decrease in the optical band gap were observed as the gamma irradiation increases. As well, the number of carbon clusters and the activation energy were discussed. The morphological investigation indicates the decrease in the roughness surface with increasing of gamma irradiation.