Magnesium-zinc alloy is a potential base material for biodegradable implant applications. In this study, the influence of zinc content (0.5-3 wt.%) in as-cast magnesium-zinc binary alloys towards the microstructure, mechanical properties and in vitro corrosion behaviour was studied. Increase in zinc content reduced the grain size of magnesium-zinc alloy. Mechanical properties such as yield strength, tensile strength and hardness improved with increase in zinc content. Potentiodynamic polarization results suggest that increase in zinc content enhanced the in vitro corrosion resistance of the alloy, which could be attributed to the combined effect of grain size refinement and even distribution of zinc on the alloy surface resulting in better passive film formation. (C) 2015 Elsevier B.V. All rights reserved.