Absorbable metallic implants constitute a technology in its infancy, with new cardiovascular and orthopedic devices (principally magnesium based) only now entering the marketplace. The technology brings a fundamental shift in the paradigm of corrosion, moving from a historical focus on its complete prevention to one of managing the entire corrosion process, including the generated degradation products. Since an implant needs to perform its structural function and also remain compatible with the body’s physiology, complete implant corrosion brings a multitude of new questions (and potential understandings). Since any medical implant needs to demonstrate a predictable level of safety, identification of appropriate standards for evaluating an implant that intentionally corrodes is needed. A collaborative effort between ASTM and ISO has been initiated to develop standardized guidance for researchers, regulators, and product developers to appropriately evaluate the composition, degradation, and biocompatibility of these new materials and their relatively complex in vivo degradation processes.