Abstract: Sulphide minerals such as pyrite, pyrrhotite, marcasite, chalcopyrite, chalcocite, galena and sphalerite are oxidizable in air and in water.Many papers point out that an excessive oxidation has unfavorable effect upon flotation, but the necessity of oxidation in flotation has not as yet been resolved satisfactorily. However, it can be said that the next conception is weighty. That is, a slight oxidation including the surface activation with oxigen promotes the floatability of sulphide minerals.For further progress of sulphide mineral flotation, more research works on this field will be necessary.