The mass attenuation coefficients of the breasts, lungs, kidneys, pancreas, liver, eye lenses, thyroid, brain, ovary, heart, large intestines, blood, skin, spleen, muscle, and cortical bone were measured at different sources (i.e., 0.021, 0.029, 0.03, 0.14, 0.218, 0.38, 0.412, 0.663, 0.83, and 1.25 MeV) using various methods including the Monte Carlo N-particle transport code (MCNP), the geometry and tracking code (GEANT4), and theoretical approach described in this study. Mass attenuation coefficients were also compared with the values from the national institute of standards and technology (NIST-XCOM). The values obtained were similar to those obtained using NIST-XCOM. Our results show that the theoretical method is quite convenient in comparison with GEANT4 and MCNP in the calculation of the mass attenuation coefficients of the human body samples applied when compared with the NIST values and demonstrated an acceptable difference.