Microwaves have been found to greatly accelerate the Biginelli synthesis of fluorine containing ethyl 4-aryl-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one/thione-5-carboxylates in unsealed vessels using ethanol as energy transfer medium. Results were compared with those obtained following the classical method. The advantages obtained by the use of microwave irradiation were demonstrated. All synthesized compounds have been characterized on the basis of elemental analyses, IR, H-1 NMR and F-19 NMR spectral studies. (C) 1998 Elsevier Science S.A. All rights reserved.