The adsorption parameters (alpha) for members of four classes of saturated hydrocarbons were compared with those observed for the corresponding ethers. The saturated hydrocarbon liquids exhibit a measurable affinity for polystyrene, as indicated by the linear relationships log alpha(f) = log alpha(i) - D-s(N-f - N-i), each characteristic of the homologous series being considered. These values increase from the linear series H(CH2)(n)H (alpha(i) = 0.10 +/- 0.02; D-s = 0.00 +/- 0.02) to those having the greatest affinity, members of the cyclic series (CH2)(n), where ai = 0.863 and D-s = 0.0875. Even the latter, however, are considerably below the values for the corresponding cyclic ethers (CH2)(n)O (alpha(i) = 3.31; D-s = 0.0888), demonstrating the superiority of an oxygen atom and a methylene unit in affinity for the polymer＇s phenyl group.