[en] The solvent extraction of zirconium and niobium di-n-butyl phosphoroditioate into organic diluents from HCl media is presented. The effect of extractant and mineral acid concentration on the zirconium and niobium distribution ratios as plots of lg. distribution ratios vs.lg.molarity of the extractant and HCl are presented. On this basis the extraction mechanism is supposed. The effect of the organic diluents against zirconium and niobium distribution ratios has been determined. (author)