H-Y zeolite modified by a radio-frequency CF4 plasma has been characterized using X-ray diffraction, nitrogen adsorption, magic angle spinning nuclear magnetic resonance, ethanol adsorption, energy dispersive X-ray and infrared absorption techniques. The ethanol adsorption measurements indicated that the hydrophobic character of the zeolite was enhanced by the plasma treatment. The energy dispersive X-ray experiments showed that the plasma-treated zeolite contained 7.91 at% of carbon and 9.93 at% of fluorine. The infrared absorption measurements clarified that replacement of -OH groups by -CF3 or -F groups on the micropore surface of the zeolite was responsible for the hydrophobic surface.