New clobutinol (Clob) ion-selective polyvinyl chloride (PVC) membrane electrodes, based on the ion-associates of Clob with phosphotungstic acid or phosphomolybdic acid were prepared using dibutyl phthalate as plasticizing solvent. The electrodes were characterized in terms of membrane composition, temperature and pH. The sensors showed a near-Nernstian response over the concentration ranges (6.31 x 10(-6))-(1.00 x 10(-2)) and (5.01 x 10(-5))-(1.00 x 10(-2))M in the case of clobutinol-phosphotungstate ((Clob)(3)-PT) applying batch and flow injection (FI) analysis, respectively, and (1.58 x 10(-5))-(1.00 x 10(-2)) and (5.01 x 10(-5))-(1.00 x 10(-2))M in case of clobutinol-phosphomolybdate ((Clob)(3)-PM) for batch and FI analysis systems, respectively. The electrodes were successfully applied for the potentiometric determination of ClobCl in pharmaceutical preparation and urine in steady state and flow injection conditions. The electrodes exhibit good selectivity for Clob with respect to a large number of inorganic cations, sugars and amino acids.