An efficient procedure for the synthesis of some N-nitroaryl derivatives of nucleobases via microwave-assisted N-nitroarylation of nucleobases in the presence of SiO2 and Cs2CO3 in DMSO, as the homogenizing solvent, is described. In this method, some pyrimidine and purine nucleobases are nitroarylated regioselectively in moderate to high yields and short reaction times.Key words: microwave, N-nitroarylation, pyrimidine, purine, SNAr.