Magnesium and its alloys are being investigated worldwide for application in biodegradable implants, yet there are no commercially available alloys specifically developed for this application. Magnesium is an essential element in the human body and it would be logical then to explore the development of alloys that contain only elements which are known to be biocompatible because they are already part of the human body. In this work, Ca, Si and Sr were selected to develop magnesium alloys for biomedical application due to their good biocompatibility. A number of ternary Mg-Ca-Si and Mg-Si-Sr alloy compositions were explored. The alloys were cast in steel molds and their phase content was measured and compared with thermodynamic predictions. The effect of the characterized phases on the hardness and compressive strength was evaluated.