Abstract The interaction of Mn(VII) and the Neotetrazolium chloride has been examined. The ion-associate formed is extracted into 1,2di-chloroethane. The optimum conditions have been established. The molar absorptivity of the complex is (9.1±0.08)×10 5 l mol −1 cm −1. The sensitivity of the method is 6.04×1010 −5 μg cm −2. It is possible to extract and determine manganese in the presence of large number of cations and anions. The characteristic values for the extraction and the aqueous phase equilibria were determined: extraction constant K ex=3.21×10 9, distribution constant K D=33 and association constant β=9.72×10 7. The method is applicable to analysis of soils and steels.