This study examines the environmental disclosure strategies of Canadian resource companies during the period 1985 to 2008. The research questions whether disclosure decisions reflect signalling or legitimization strategies by studying the relation between the companies’ environmental disclosure and their actual environmental performance, and by examining the nature of changes in disclosure when seven environmental reporting regulations are introduced over this period. We use non-parametric tests, ANCOVA and charts to examine the types and quantities of information disclosed and changes in these over time. We find evidence of signalling behaviour, but we also find that as reporting regulations increase, companies shift information out of the annual report and into standalone corporate environmental and social responsibility reports which have, during the study period, no independent auditor involvement.