The mechanical properties and corrosion behaviour of AZ91 magnesium alloy containing 0.2-0.5 wt.% Ti were investigated in this study. Results demonstrate that the enhancement of the ultimate tensile strength by 18% and yield strength by 47% can be achieved by Ti addition. The corrosion behaviour was evaluated by immersion tests and potentiodynamic polarisation measurements in 3.5% NaCl solution. The results from the immersion tests and potentiodynamic polarisation measurements showed that the corrosion resistance of AZ91 alloy increased progressively with the increase of the Ti content of the alloy. Compared to AZ91 alloy, 0.5Ti addition increased the corrosion resistance by up to 45 fold. The mechanism of property enhancement is ascribed to both the suppression of partially divorced beta-Mg17Al12 eutectics and an increased Al content in alpha-Mg solid solution by Ti addition in AZ91 alloy. (C) 2010 Elsevier B.V. All rights reserved.