Under the conditions we dealt with, only wQstlte is stable in the system Fe-Mo-O while molybdenum is reduced and passes into the solution. Practically with all compositions of the solid solution iron is predominantly chlorinated, and it passes into the molybdenum. Therefore the alloy iron-molybdenum can be obtained through the chloride phase only by chlorination of pure molybdenum. Chlorination of iron oxides and molybdenum oxides in the presence of hydrogen is inefficient because it is difficult to ensure the necessary composition of the gas phase. The results of the present work can be used for working out technological regimes of alloying the surface of iron objects through the chloride phase and for obtaining powdered alloys Iron-molybdenum.