The cathodic behavior of molybdenum electrode has been investigated in model glass melt of the basic composition of 16Na(2)O, 10CaO, 74SiO(2) (wt.%) with additions of SO3 or Sb2O3 or without additions at 1400 degrees C There exists a range of cathodic potentials reduced by some hundreds millivolts against the rest state where the reduction of electroactive species acting as depolarizers of molybdenum corrosion may be suppressed. The potentials of the maximum suppression of lead or antimony precipitation correspond to potentials at which the anodic molybdenum oxidation finishes. The layers of molybdenum silicides have been not found on the electrode at those potentials. In glass melt containing sulfur trioxide, the sulfur depletion of glass in electrode vicinity takes place. At more reduced potentials, the subsequent formation of silicon and formation of the silicides Mo3Si, Mo5Si3 and MoSi2 occurs. The formation of silicon and silicides is impeded by presence of the electroactive glass components mentioned above. The overall cathodic current increases at the same time. That is probably due to the preferential reduction of the electroactive species by reduced alkali metal