A model is presented to evaluate the effect of the roughness and the profile of concentration of hydrogen in a low carbon steel.The model takes advantage of the Pick's Second Law, to predict the transport of hydrogen in the steel.The problem is treated as a variational one and its space solution is made numerically by means of the Finite Elements Method, while the temporal equation is solved via the Finite Differences Method, in order to determine the concentration profiles c: »f Hydrogen in the steel and to quantify the roughness effect.Simultaneously, bipotentiostatic hydrogen permeation test were performed to evaluate the coefficient of mass transfer.