The hydrophobic micropores of active carbon were filled with a mixture of water and ethanol by adsorbing their mixed vapors (H2O/EtOH = 3/1) on active carbon, The desorption isotherm of each component from the micropores has been determined simultaneously at 25 degrees C by a combination of volumetric and gravimetric methods. A more selective desorption of water than that of ethanol was discovered from the measured isotherms, It has been clarified from the present finding that the separation of water and ethanol could be carried out by means of an adsorption technique using a hydrophobic active carbon adsorbent, The preferential desorption of water may be attributed to the weak interaction of water with the hydrophobic micropore surface in comparison with the interaction of ethanol with the micropore surface. The adsorption energy of water on the micropore surface is 17-32 kJ mol(-1) at low coverage, while that of ethanol on the micropore surface is 43-52 kJ mol(-1), The possibility of enrichment of ethanol from its dilute aqueous solution made by fermentation was discussed on the basis of the present desorption data.