[en] This work aims to calculate the fluence to effective dose conversion coefficients, (E/Φ), for monoenergetic neutrons from 10^-9 to 20 MeV, based on the radiation (w_R) and tissue (w_T) weighting factors values recommended by ICRP publications numbers 60 and 103. The organs and tissues absorbed doses were calculated using the radiation transport code MCNPX and a female anthropomorphic voxel-based simulator, assuming whole-body irradiation by plane-parallel beams, on the geometries of the antero-posterior (AP) and postero-anterior (PA) irradiation. Dose calculations were performed for 21 selected organs of the body, for which the International Commission on Radiological Protection and the International Commission on Radiological Units and Measurements have set tissue weighting factors for the determination of the effective dose. From comparison between the dose results calculated and the data reported for the MIRD model, it can be concluded that, the fluence to effective dose conversion coefficients obtained using the voxel simulator are underestimated by a factor of up to 5 times when compared with the one obtained by ICRP 74, using mathematical simulators. (author)