MCNP calculations for a benchmark representative of the fusion blanket neutronics shielding in SINBAD (Shielding Integral Benchmark Archive Database) were performed by using the four nuclear data libraries, ENDF/B-VII, JEFF-3.1, JENDL-3.3, and FENDL-2.1. Neutron and gamma flux spectra were calculated at two positions in a mock-up of the ITER inboard shield system. The results were compared with each other and also compared with measured data from the neutronics experiments for the ITER shielding blanket. For neutron spectra calculations, it is noted that the MCNPX calculations using all libraries agree well with experiments at positions A and B. For gamma spectra calculations, an overall good agreement can be stated and the tendency of a slight underestimation with penetration depth is observed.