The adsorption of benzothiophene from fuels on NaY zeolites modified with 0.09 M NaOH aqueous solution was investigated. The sulfur removal reached to 99.9%, and the adsorption capacity was 1.65 mg benzothiophene/g of the modified adsorbent. The results of the scanning electron microscopy, X-ray diffraction, X-ray fluorescence, and N-2 adsorption-desorption isotherms analyses show that mesopores appeared on the surface of NaY-0.09 adsorbent and the intrinsic crystallinity was preserved after the modification. Py-IR and NH3-TPD analyses indicated that the adsorption of benzothiophene occurred on the weak Lewis acid sites on the adsorbent. Both an increase in the number of the weak Lewis acid sites and the formation of mesopores on NaY-0.09 adsorbent improved its desulfurization activity. (C) 2015 Elsevier B.V. All rights reserved.