Transient electrochemical techniques showed that in NaCl-KCl melts the reduction of K2NbF7 occurs through atwo-step reaction Nb(V) --> Nb(IV) --> Nb. When oxide ions were introduced, cyclic voltammetry indicated that the wavescorresponding to reduction of the complex NbF72- progressively disappeared. Oxo complexes, such as NbOFn(n - 3)-, arereduced at a potential close to that of the Nb(IV) fluoro complexes. Niobium metal deposition was perturbed by theformation of niobium suboxides like NbO or Nb4O5. For molar ratios of oxide to Nb greater than one a black layer ofniobium oxide NbO2, appeared at the electrode surface. The present study confirms the high oxygen affinity of niobiumand shows that a careful purification of the electrolyte and feeding materials is required for producing niobium with a lowoxygen content.