Historically, cobalt-chromium, stainless steel and titanium alloys have been the main principal materials used in a variety of medical procedures for load-bearing implants in the body. Magnesium and magnesium-based alloys have the potential to be used as short-term structural support during the healing process of damaged hard tissues and diseased bone. Unlike traditional biologically compatible metals, which are not biologically degradable, magnesium based alloys offer both biological degradability and biological absorbability. Despite the many advantages offered by magnesium, its rapid degradation rate in the highly aggressive and corrosive body fluid environment has severely limited its present day medical application. This article reviews the chemical immersion technique for producing calcium phosphate coatings on magnesium substrates for slowing down the degradation rate while maintaining the biological compatibility and absorbability.