The as-cast Mg-3Sn-2Ca alloy shows a good creep resistance that is better than that of AE42 alloy. The high content of alloying additions in these alloys results in low ductility due to the presence of primary intermetallic particles. The effect of reduced amount of Ca and Sn, below the maximum solid-solubility limit of each alloy additive, was studied to determine the potential of the Mg-0.8Ca-xSn alloys in structural applications. The microstructure of the alloys resulting from different processing routes was characterized and the corrosion resistance of the alloys measured to determine the best combination of alloy composition for further alloy development.