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A new composite material of W–Bi2O3 system is proposed as a protection against ionizing radiation. An improved method of hot isostatic pressing for the preparation of composite materials is proposed. The duration of sintering under conditions of high pressure and temperature was 3 minutes. The study of the morphology and chemical composition of W–Bi2O3 composites was carried out using scanning electron microscopy and X-ray energy-dispersive spectroscopy respectively. The density evaluation of the obtained materials was carried out using the Archimedes' method. The densest samples were obtained at a pressure of 5 GPa and temperatures of 25 and 500 °C, the density of which was 18.10 and 17.85 g/cm3, respectively. It is shown that exposure to high temperatures during sintering adversely affects both the microstructure and density of the samples due to the redox reaction accompanied by the reduction of Bi and the oxidation of W. The results of studying the W–Bi2O3 structure by X-ray diffraction analysis showed that all samples include the main body-centered phase W, and the presence of the WO2 phase is noted only when the sintering temperature is increased to 850 °C, which is confirmed by the appearance of reflections 111 and 22-2. Shielding effectiveness of the W–Bi2O3 composite materials from gamma radiation using the Phy-X/PSD software was evaluated. Co60 with an energy of 0.826–2.506 MeV was used as a source of gamma quanta. The simulation results were compared with the calculations for Pb and Bi. Key parameters such as linear attenuation coefficient, mean free path and half value layer are determined. The calculation results showed that the W–Bi2O3 composite surpasses Pb and Bi in its shielding properties, which makes it promising for use as a radiation shielding material.