Nitrogen adsorption, at 80.2 K, on a series of amorphous carbonaceous materials is studied. To verify the hypothesis that all these materials share similar surface characteristics, two structures generated following different approaches are employed. GCEMC and CEMC computer simulations are performed to calculate nitrogen adsorption isotherms and the Corresponding heats of adsorption. Simulation results are compared with experimental data obtained in our laboratory and from the literature. The agreement between the simulations and experimental results is quite good confirming the amorphous nature of the surface of these materials.