The present work aims to study the effect of the CuSO4 additive on the physical and radiation-shielding properties of polyepoxide resins. As a result, a series of four samples with the chemical composition xCuSO4 + (100 - x) (epoxy resin and hardener) was synthesized. The fabrication of samples was performed under atmospheric pressure and at room temperature. The density of the fabricated CuSO4-doped polyepoxides resin was measured experimentally using an MH-300A densimeter with an accuracy of 0.001 mg·cm-3. A narrow beam transmission method with an NaI (Tl) detector was used to evaluate and describe the effect of CuSO4 on the linear attenuation coefficient of the fabricated composites in the γ-ray energy interval, which ranged between 33 and 1,332 keV. The estimated results showed a high enhancement in the μ values that increased from 0.259 to 1.749 cm-1, raising the CuSO4 concentration from 0 to 40 wt% at a γ-photon energy of 33 keV. The enhancement in the μ values decreased with an increase in the γ-photon energy to 1,332 keV, whereas the μ values increased from 0.077 to 0.102 cm-1 with an increase in the CuSO4 concentration between 0 and 40 wt%, respectively. This showed that increased μ values positively affected the half-value thickness (Δ0.5, cm), mean free path (λ, cm), lead equivalent thickness (Δeq, cm), and the transmission factor (%); all of the mentioned parameters suffer a considerable decrease with increasing CuSO4 concentration between 0 and 40 wt%. © 2023 the author(s), published by De Gruyter.