Extraction of tungsten (VI) and molybdenum (VI) from acidic solutions by hydrazides (N′, N′-dimethil hydrazides) of branched higher carboxylic acids of fractions Versatic 10 and Versatic 1019 with different number of carbon atoms has been studied. Extraction reagents have been synthesied in hexane by acylation of 1,1-dimethyl hydrazine and fractions by acid chlorides of Versatic acids fractions. Reagents have been identified by means of instrumental methods. Solutions of extraction reagents in neutral and protonated forms have been prepared in aviation kerosene. Optimum conditions for tungsten (VI) extraction have been specified depending on pH systems, concentrations and forms of extraction reagents. The technique for efficient extractional separation of tungsten (VI) and molybdenum (VI) from acidic solutions at their copresence and the mechanism of extraction have been offered.