Abstract: A new selective electrode sensitive to berberine was developed. It is based on the use of berberine-tetraphenylborate ion-pair complex in polyvinyl chloride membrane, dibutylphthalate being used as the plasticizer. The electrode showed Nernstian respones down to 10^-6 M over a pH range of 6.2～11.5 with cationic slope of 57 mV/concentration decade. Selectivity coefficients for jatrorrhizine anal some other alkaloids are small. Direct potentiometric determination of samples and potentiometric titration with rodium tetraphenylborate can be used for the determination of berberine.