The use of radiation continues to develop day by day in the fields of medicine, industry, agriculture and nuclear power plants. The protection of the employees and the public from the harmful effects of radiation is another important issue besides the development of nuclear technologies. In this study, some hexaborides (LaB6 and CeB6) synthesized in our chemistry laboratory were analyzed by X-ray diffraction (XRD) and their average crystal sizes were calculated using the Debye Scherrer equation. The gamma ray shielding properties of these samples, which were observed to be nano-sized, were then investigated. In order to determine the gamma ray shielding properties of the samples, the mass attenuation coefficients, half value thickness, one-tenth value thickness, mean free path values were calculated using the Monte Carlo method. In this method, calculations were made in the photon energy range of 10-3 MeV – 106 MeV, and the resulting data were compared with the ones calculated by the XCom program. Here, using MC and XCom, these results obtained for the investigated compounds were compared with the results obtained for the radiation shielding standard materials such as lead, vermiculite, borosilicate, concrete and granite too. As a result, a successful consistency was observed and it was concluded that the produced hexaborides had very promising gamma protection properties compared to the materials previously investigated in the literature.