The present work deals with developing a HA coated Mg alloy material system for application in orthopaedic implants. A nanostructured hydroxyapatite (HA) coating was grown on selected Mg alloy (Mg-3Zn) through the electrophoretic deposition (EPD) technique. The mechanical integrity of the coating is established as a function of surface roughness of the substrate and annealing temperature of the coating. Coating on a substrate with lower roughness shows a uniform layer and very few cracks. The mechanical properties of the surfaces help in optimizing the coating conditions to get a better integrated HA coating on the Mg surface. The HA coating shows an impressive 25 times improvement in corrosion resistance of the Mg alloy surface during in vitro exposure. The coating also helps in better growth of bone cells on the Mg surface. This study establishes the potential of electrophoretic deposition of HA coating on Mg-3Zn alloy in orthopaedic application. © 2016 Elsevier B.V.