Using a truncated Lennard-Jones (6-12) interaction potential for the molecular interactions, we have calculated thermodynamical excess functions of various binary mixtures from Barker-Henderson perturbation theory. In the calculations of thermodynamic quantities, we used the Carnahan-Starling equation of state as a hard sphere reference system. It is seen that our results are quite satisfactory when compared to the existing theoretical and experimental results. Copyright © 2002 Elsevier Science B.V.