This work is dedicated to the study of the growth kinetics of the borided layers obtained by the paste-boriding process. A diffusion model based on Fick's laws and coupled with a thermodynamic description of the Fe-B binary system was suggested to simulate the growth kinetics of the borided layers consisting only of Fe2B phase and containing 8.83 wt.% B onto the iron substrate within the temperature range of 1223-1323 K. The validation of the diffusion model was achieved by comparing the simulation results with the experimental data taken from the literature and a good agreement was observed. Furthermore. the model was able to predict the boron-depth-concentration profile for Fe2B phase as well as the thickness of the borided layers depending on the boriding parameters. (C) 2004 Elsevier B.V. All rights reserved.