In this study, gamma shielding properties of concretes containing magnetite and limonite ores at different ratios (5%, 10%, 15%, 20%, and 30%) were investigated by using a Co-60 (1.25 MeV) radioactive source which was built in Thratron 1000E (TM) device used for radiotherapy purposes. Then, the photon transmission values (I/I-0) were measured by 0.6 cm(3), farmer type, PTW (TM) ion chamber. The dose readings (I-0 and I), made by PTW (TM) Unidose Electrometer, were used to calculate the linear attenuation coefficient (mu, cm(-1)), the mean free path (lambda, cm), and the mass attenuation coefficient (mu(rho), cm(2)/g) by the Lambert equations, and the results were compared with the calculations obtained using the WinXCom computer program. The findings from this study revealed that the concretes containing magnetite and limonite ores were more effective than the ordinary concrete in the attenuation of gamma rays. It was determined that the values of the mean free path decreased with the increasing concentrations of magnetite and limonite ores while the linear attenuation coefficients for 10 concrete blocks increased with the increasing magnetite and limonite ore concentrations. A comparison of the theoretical values obtained from the WinXCom computer program and the experimental results revealed a good level of conformity.