Gamma ray attenuation coefficients of metal matrix composites have been investigated. For this purpose, the linear attenuation coefficients of composites containing boron carbide (B4C) at different rates have been measured using a gamma spectrometer that contains a NaI(Tl) detector and MCA at 662, 1173 and 1332 keV, which are obtained from Cs-137 and Co-60 sources. The measured results were compared with the calculation obtained using computer code of XCOM for 1 keV-1 GeV gamma energies.