Aluminum-magnesium alloys can potentially be used as hydrogen storage materials. In order to enhance the kinetics of hydrogenation, it is desirable to have agglomerates of fine powders with very small grain size. Electrodeposition is a viable method to produce pure powders with an ultrafine structure. In this paper we report the effect of magnesium content, electrolyte temperature, and current density on the characteristics of Al-Mg deposits produced galvanostatically using an organometallic-based electrolyte. The magnesium content of the deposits improved with increasing Mg concentration in the electrolyte, temperature, and current density. The results indicate that the morphology of the deposits is significantly affected by the magnesium content. Depending on the composition, the deposits consisted of face-centered cubic-Al(+Mg) and hexagonal close-packed-Mg(+Al) phases. (C) 2008 The Electrochemical Society.