Some AM60B magnesium alloys sheets produced by High Pressure die Casting were Friction Stir Processed and the mechanical and microstructural features are presented in the present study. The mechanical properties of the FSP material were analyzed in longitudinal direction respect to the processing one and compared with those of the base material. Tensile tests were performed at room and high temperature and different strain rates in the nugget zone, in order to analyse the superplastic properties of the recrystallized material and to observe the differences respect to the base material after the strong grain refinement effect due to the Friction Stir Process. The high temperature behaviour of the material was studied, in longitudinal direction, by means of tensile tests in the temperature and strain rate ranges of 175-250 degrees C and 10(-2)-10(-4)s(-1) respectively. (c) 2006 Springer Science+ Business Media, Inc.