Magnesium alloys are gaining increasing interest in light weight applications in automotive industry. Due to industrial requirements alloy development is of major importance to achieve an improvement of the property profile. Unfortunately the use of alloying elements like rare earth elements, calcium, silicon, strontium etc. is also decreasing the castability and alloys containing these elements have not yet been introduced to continuous casting as well. Therefore the new alloys have to be selected carefully in accordance to their castability regarding different casting processes. In this work AZ based alloys modified with Ca and Zn will be investigated regarding their hot tearing behavior.