Surfactant ion-selective electrodes, prepared by coating silver wire with a suitably conditioned electroactive poly(vinyl chloride) polymer, have been found to show an excellent Nernstian response to both anionic (sodium dodecyl sulfate) and cationic (tetradecyltrimethylammonium bromide) surfactants. When conditioned to a specific surfactant, electromotive force data show a much larger response range to lower surfactant concentrations (<5 x 10(-7) mol dm(-3)) and also greater long-term stability when compared to previously formulated membrane-type surfactant ion-specific electrodes.