The objective of this study is to investigate the mass attenuation coefficients (μm) of lanthanumhexaborides and ceriumhexaborides over a wide photon energy range emitted from the main radioactive sources used in medicine and industry. 125I, 99mTc, 131I, 137Cs, 60Co and 152Eu gamma ray sources were used in the experiments. The materials synthesized in powder form were first pelletized and then irradiated by photon beams. At the end, it was seen that there is successful consistency between the obtained experimental data and the previous theoretical results. It was also observed that the investigated samples are comparable enough to the known standard gamma shielding materials, especially to lead which is one of the most common one. In conclusion, it is understood that the presently investigated samples have a promising aspect in terms of developing new shielding materials against gamma rays.