This study is to predict adsorption equilibrium data for their binary gas mixture systems from pure gas adsorption data of CO₂, CH₄, C₂H₆ and C₃H₈ on zeolite 5A (Davison C-625). A nonlinear regression method and an optimization method were employed in the calculation of the parameters. The binary mixture adsorption data have been examined against values predicted by various models using regression parameters obtained from the single component isotherms. For these systems the W-VSM gave the best representation of the experimental data. C₃H₈-CO₂ system formed an azeotropic mixture at 325.15K and 12.26kPa. Isosteric heat of adsorption for carbon dioxide, methane, ethane and propane were 10.79kcal/mol, 6.95kcal/mol, 9.2kcal/mol, 11.85kcal/mol, respectively.