The tensile tests and the Erichsen tests at room temperature have been performed on seven kinds of Mg alloys: Mg-1.5Zn, Mg-1.5Zn-0.1Ca, Mg-3Zn, Mg-3Zn-0.1Ca, Mg-3Al, Mg-3Al-0.1Ca and Mg-1Al-1Zn-0.1Ca-0.5Mn alloys. In the Mg-Zn alloys, the 0.2% proof stress at 90 degrees, which was the angle between the tensile direction and the RD, was decreased by addition of Ca, while the 0.2% proof stress at 0 was increased by addition of Ca. Also, an increase in elongation to failure by addition of Ca at 90 degrees was larger than that at 0 degrees. However, such variations in tensile properties by addition of Ca were not found in the Mg-Al alloy. The stretch formability for the Mg-Zn alloys was significantly enhanced by addition of Ca, while the stretch formability of the Mg-Al alloy was not enhanced by addition of Ca. These results by the mechanical testing are ascribed to the variations in basal texture by addition of Ca. [doi:10.2320/matertrans.M2011048]