The reversibility of electrochemical magnesium deposition from Grignard reagents was investigated with regard to potential application of magnesium as a negative electrode in rechargeable batteries. The reoxidation rate depends on the morphology of the magnesium deposit which is controlled by the substrate material. Good results were obtained using silver or gold substrates. Magnesium deposits on these materials was found to be of smooth and compact morphology. A nearly complete electrochemical reoxidation and a low self-discharge were observed.