There is growing interest in magnesium alloys as structural materials for the automotive, aerospace and electronic industries. However, the corrosion performance of most magnesium alloys is not good enough for the increasingly diverse practical applications. The Cooperative Research Centre for Cast Metals Manufacturing (CAST) is an Australian research organisation established to cope with the problems associated with development and application of light metals. Corrosion and prevention of magnesium and its alloys has been an important part of CAST’s research program since 1995. The research effort in this area is focused on solving corrosion problems relative to the application of magnesium alloys in the automotive industries. Nevertheless, encompassed by the requirements of the applied research, some fundamental studies have also been conducted. This paper presents a brief summary of some of the research achievements in this area recently made by CAST. They include studies of corrosion behaviour, alloying effects, corrosion inhibition and surface treatment of magnesium alloys.