The radiation-shielding capabilities of high-performance concrete (also known as HPCs) were investigated experimentally by several different variables. The production of HPCs with varying compressive strengths is required using three different low water-to-cementitious material ratios (w/cm) and several distinct types of normal and heavyweight aggregate. To calculate the linear attenuation coefficients of radioactive 137Cs at 0.663 MeV, a NaI(Tl) scintillation detector was used. We found that the compressive strength of heavyweight HPCs plays a significant role in the enhancement of ????-ray attenuation. It is possible to draw a linear conclusion about the relationship between the compressive strength and the attenuation of -rays. Regarding regular concrete, the strength does not affect the amount of -radiation absorbed by the material—comparison of results from the US National Institute of Standards and Technology and mass attenuation coefficients. There was a reasonable amount of agreement between the two. Density affects ????-ray attenuation.