Tertiary phosphine oxides have been synthesized by the reaction of secondary phosphine oxides with diverse hetarylmethylchlorides (pyridines, imidazoles, pyrazole) in the superbasic systems CsF/NaOH/DMF/4 Å MS or NaOH/DMSO/4 Å MS at 23-25 °C. It is found that a tertiary phosphine oxide bearing the imidazole fragment possess the pronounced antimicrobial activity.