We report experimental measurements of the adsorption of methane and ethane, and binary mixtures of these components, on MCM-41. This adsorbent, which has a simple, regular pore structure and a chemically homogeneous surface, was used as a model system on which to evaluate methods for the prediction of adsorption equilibrium. Two methods were evaluated: ideal adsorbed solution theory and grand canonical Monte Carlo simulation. Both methods gave accurate predictions of binary adsorption. In addition, the grand canonical Monte Carlo method was able to accurately predict pure-component adsorption.