In the present study, the effects of Sn addition on the microstructure and mechanical properties of Mg-MM (MM: misch metal) have been investigated. To optimize the mechanical properties of Mg-MM-Sn alloys, the effects of addition of Al or Zn have been further investigated. The secondary solidification phase in Mg-MM alloy changes dramatically with addition of Sn forming small rod-shaped phase. Although the strength of alloy is decreased with addition of Sn, the ductility is improved in Mg-rich Mg-MM-Sn alloys. To enhance the mechanical properties, a small amount of Al and/or Zn has been added in Mg-2MM-2Sn alloy. The rollability and mechanical properties are improved with addition of Al or Zn. From the result of conical cup test at 200 °C, it has been found that the addition of alloying elements improved the formability of Mg-MM-Sn alloys.