Adsorption isotherms at 283 and 303 K of methane, ethane, and ethylene on zeolite G5 have been obtained. Measurements have been made at pressures up to 1200 kPa using an automated apparatus based on the volumetric method. This study is linked to a modeling interest because of the structure simplicity of the adsorbate molecules and because of the known geometric structure of the adsorbent.