Alkylation of benzene with aqueous solution of ethanol (commercial 95 % purity) has been done in a laboratory scale reactor with ZSM-5 zeolite diluted with silica as a catalyst. The experiments have been done using different ratios of SiO2/Al2O3 catalysts in the reactor to study the change of activity and selectivity of desired product. Alkylation of benzene with aqueous ethanol yielded ethylbenzene as the primary product and lower amount of diethylbenzene isomers. With changing silica to alumina ratio in unmodified ZSM-5 catalysts, it was supposed that the influence caused by the existence of water in the reactants on acid-catalysed reaction is also changed. Modified B- and Mg- types of ZSM-5 zeolites were also examined. There were only small differences between 100% ethanol and 95% aqueous solution of ethanol in the experiments related to alkylation. Thus, it was inferred that it is possible to use 95% ethanol and water mixture as alkylating agent and ZSM-5 catalyst as a catalyst.