The tensile properties of extruded Mg-Sn-Al-Zn alloy at elevated temperature were investigated. Low-temperature superplasticity was found in the alloy, which exhibited tensile elongations of 410-950% at strain rates in the range 1 x 10(-3)-1 x 10(-4) s(-1) at 473 K. The superplastic deformation behavior was attributed to the fine-grained microstructure, which contained thermally stable Mg(2)Sn precipitates.