The adsorption equilibria of pure methane and ethane gases as well as their binary mixtures were measured on a template-synthesized carbon. The pure component isotherm data were fitted to the Sips equation, while the binary equilibria were studied by the extended Sips equation as well as the ideal adsorbed solution theory (IAST). It was found that the IAST performed better than the extended Sips in predicting the binary data on the highly heterogeneous carbon sample.