The tenaammetric behavior of di-(2-ethylhexyl)phosphoric acid (D2KHPA) was investigated by non-phase-selective AC polarography. D2EHPA produces in alkali sulfate supporting electrolytes a decrease of the capacitive current in the region of zero-charge potential, as well as a tensammetric peak located between -1.0 and -1.3 Vvs. SCE. In the same range, the second harmonic has a characteristic maximum. The pH of the solution and the nature of the cation in the supporting electrolyte affect both the height and the position of the tensammetric peaks. The tensammetric method allows determination of D2EHPA at concentrations ranging from 0.5 to 200 mg/1. Maximum sensitivity is obtained by measuring the second harmonic.