[en] Using the methods of thermogravimetry, infrared spectroscopy and analytical analysis electroreduction of WO₄^2- and MoO₄^2- from fluoride-containing electrolyte is studied. It is established that products of incomplete reduction of tungstate- and molybdate ions present heterogeneous systems consisting of oxide-hydroxide compounds of lower valencies, possesing mixed conductivity. Complete reduction of WO₄^2- and MoO₄^2- to metal takes place at high concentrations of fluoride-ion (>= 50 g/l) and high current densities: 100-400 A/dm² for molybdenum and 100-200 A/dm² for tungsten