The adsorption isotherms of n-decane and n-dodecane on amorphous poly(cyclohexyl methacrylate) in its glassy state have been determined from the profiles of gas chromatographic peaks. The isotherms obtained are characteristic of a low surface energy solid. The possible influence of the experimental variables flow rate and sorbate sample size on the isotherms thus determined has been investigated. The BET model of multilayer adsorption, when applied to the isotherms, yields an estimated specific surface area of the adsorbent which is too large in comparison with literature values for other polymers. This discrepancy is attributed to the penetrable nature of our polymer. Its cyclohexyl side group should impart enough free volume to the solid below T to allow for the penetration of the sorbate molecule.