The corrosion resistance of conventional and experimental Mg-3Al-1Zn-based alloys with different Mn and Y content was comparatively investigated. After immersion for 72 h in a 0.6 M NaCl solution at 25 degrees C, an experimental Mg-3Al-1Zn-0.05Mn-0.03Y alloy exhibited a corrosion rate of 0.91 mm y(-1), which is about four times slower than that of a conventional Mg-3Al-1Zn-0.3Mn alloy. Microstructural factors underlying the improved corrosion resistance achieved by the trace additions of Mn and Y are discussed.