Adsorption equilibria and mass transport properties for ethyl acetate on activated carbon have been evaluated in the presence of supercritical carbon dioxide by means of the impulse response technique. A two-column system, one for dissolving solute and one for adsorption, was used to evaluate the phenomena purely in the adsorption column, The adsorption equilibrium constant was larger for higher temperature and lower pressure. The apparent heat of adsorption calculated from the temperature dependence of the adsorption equilibrium constant was 30-40 kJ/mol. The intraparticle effective diffusivity was larger for higher temperature and lower pressure. The Peclet number that relates to the axial dispersion coefficient was 0.08-0.39. These estimated parameters are in good agreement with those obtained from desorption measurements reported in the literature.