The melting process of magnesium alloys must be performed in a more specific way than the other metallic materials. If any protective measures are not taken during the melting process of magnesium alloys, molten magnesium reacts in an exothermic reaction with the oxygen in the air at temperatures above 475°C. This severe reaction may not be held under the control. And also, the eutectic phase Mg17Al12 begins to the oxidation at 430°C. Therefore, the aluminum-containing die-casting magnesium alloys should be protected from temperatures above 400°C, before the melting process begins. The protection with the protective gases (fluxless method) is preferred for the high pressure die casting process of magnesium alloys. The most effective protective atmospheres used in die casting of magnesium alloys are the mixtures containing fluorinated gases such as SF6, BF3 and HFC (Hydrofluorocarbon). As an alternative to these, SO2/air or SO2/N2 mixtures can be used as the protective gas. In addition, melting without a protective gas atmosphere will may be possible with the new developed alloys by the addition of very small amounts of beryllium or calcium. This paper investigates the present works about the protective atmospheres used for melting process of high pressure die casting magnesium alloys in the literature, and the industrial area; and represents a comparison among the differences of the alternative mixtures of the cover gases.