Biodegradable implants have many advantages over conventional steel and titanium based implants. Most important one of these advantages is the ability of these implants to degrade within a desired span of time (compatible with tissue and bone growth) after their function is over, without giving any harm to the body. The aim of this study is to develop a magnesium based biodegradable implant to be used as a bone plate. Mechanical and physical properties of Mg alloys that should possess for these applications are almost completely established, whereas the applicability still has to be investigated. In this study, Mg/MgZn/Zn composites were produced by mechanical alloying and hot pressing. Biodegradability of Mg/MgZn/Zn composites was tested as in-vitro in simulated body fluid (SBF) solution. SBF is nearly equal to human body blood plasma with ion concentrations. Seven implants were produced. They were placed in SBF solution and then their corrosion resistances were followed. During the process, visual changes of the implants were observed, pH, Mg ion concentrations of SBF solutions and mass, dimensional changes of degraded implants in solutions were measured. As soon as, implants were placed in SBF solutions, gas outlet of H 2 was observed, because of Redox reaction, which took place between implants and SBF. The composites in SBF remained between 1-360 hours and Zn% 2.35 and 3.10 had the longest degradation time when compared to others. Therefore, only three of the composites Zn% 0 (7h), 2.35 (360h) and 3.10 (192h) were selected for further, SEM and mechanical control tests.