this report reviews the corrosion related properties of magnesium, magnesium alloys, and magnesium based composites. it attempts to place in perspective the corrosion behavior/limitations of these materials in environments likely to experienced by naval systems these are treated from both macro- and microscopic perspectives. the role of base metal impurities is investigated. the strengths and limitations of the more traditional corrosion protection methods are discussed. some modern non-paint surface treatments and still experimental anticorrosion surface modification techniques are assessed for magnesium. special emphasis is given to the magnesium-graphite fiber composite system, identified as unique for certain space satellite applications by virtue of its very high stiffness, near zero coefficient of thermal expansion (cte), and high electrical conductivity. some evidence of potential corrosion problems with this composite material in the prelaunch environment and a mechanism possibly responsible for this are presented relatively brief discussion is devoted to achieving the desirable properties of gr/mg composites using alternative materials. finally some recommendations are made for corrosion protection of magnesium-based materials for naval systems in light of recent research efforts. additional consideration again is given to the potentially important gr/mg composite system