In order to improve the adsorption performance of the carbon-based adsorbents for sulfur removal from liquid hydrocarbon fuels, two commercial activated carbons (AC), coconut-based (microporous) and coal-based (mesoporous) were oxidized by using different oxidation agents such as nitric acid, ammonium persulfate or hydrogen peroxide. The adsorptive performance of the initial and oxidized AC samples was evaluated in a batch system by using a model diesel with 390 ppmw of sulfur and a real diesel with 325 ppmw of sulfur, respectively. The structural properties and surface chemistry of the starting and the oxidized AC samples were characterized by using the nitrogen adsorption and the temperature programmed desorption (TPD) technique. The effects of the different oxygen groups and textural properties of the oxidized samples on adsorption desulfurization of the model and real diesel fuels were examined and discussed. The results showed that the adsorptive desulfurization is dependent on both the porosity and surface chemistry of the carbons. The improvement of the oxidation modification for adsorptive desulfurization performance is different for mesoporous and microporous ACs.