This work focuses on the study of changes in the optical transmission of Y 2 SiO 5 :Ce crystals caused by ionizing radiation from γ-quanta and high energy protons. Radioisotope content of proton-irradiated crystals, transmission and induced absorption spectra, and scintillation characteristics are measured after irradiation with protons. In contrast to crystals of heavy complex oxides, Y 2 SiO 5 :Ce crystals do not demonstrate significant deterioration of transmission in the luminescence range (400–600 nm) under irradiation. Such crystals can be considered as a material for construction of detecting cells of the calorimetric detectors at LHC with high luminosity. The feasibility of growing large crackless Y 2 SiO 5 :Ce crystals with a diameter up to 50 mm and length up to 250mm is demonstrated