Summary This article contributes to the debate over the willingness, ability and sincerity of transnational corporations (TNCs) to improve their environmental and social records. It draws on recent research conducted in southeast Madagascar where Rio Tinto is currently assessing the possibilities of establishing a large mining venture. By assessing the situation as it develops, it is hoped to highlight policy issues that will help allow the rhetoric of environmental and social concern to be turned into reality. The article explores why TNCs seek to gain environmental and social legitimisation for their activities, who their efforts are aimed at, and how they attempt to gain such legitimisation. Both the positive aspects of this legitimisation process and areas of concern are presented before the policy implications are examined. The article concludes that the topical nature of the case study means the integrity of current efforts still remains to be seen, and significant barriers, in particular not recognising indigenous land rights, still need to be overcome before claims of ‘greenwash’ can truly be dismissed.