The epoxides (styrene oxide and 1,2-epoxyhexane) reaction with ethanol was carried out, catalysed with acidic activated carbons. The reactions were carried out under microwave irradiation. In the 1,2-epoxyhexane reaction, high yields were attained in some of the reaction conditions tested, although the regioselectivity was not high. For the styrene oxide reaction, the conversion was higher and the regioselectivity was high in most cases. For comparison, the reactions have been also performed in a batch reactor system under thermal activation.