The subject of this research was to monitor and evaluate the effect of X-rays and e-beam irradiation on the structure of nanoscaled TiO2 and its properties. The samples of nanoscaled TiO2 were synthesized using the sol–gel method and subsequently exposed to thermal treatment to obtain the anatase crystalline structure. X-ray powder diffraction (XRPD) and Raman spectroscopy revealed the following changes in the structure as a result of the e-beam and X-ray irradiation: a decrease in the size of the crystallite of TiO2, an increase of the distance between the crystalline planes and the lattice parameters as well as the achievement of a certain degree of amorphization. As a consequence of the structural changes, thermal stability decreased. Also, a shift of the light absorption toward the visible end of the spectrum was detected and the energy of the band gap was reduced, indicating a better photocatalytic activity, i.e., the photocatalytic action can be shifted to the region of the visible light.