A wide variety of anthropogenic chemicals are accumulating in the marine environment due to the expansion of urban, industrial, and agricultural developments along the Australian coastline. Marine megafauna can be useful indicators of the health of the marine environment due to their susceptibility to contaminant bioaccumulation and biomagnification from their position at the top of marine food chains and their long lives. The last review of contaminants in Australian marine megafauna was over 25 years ago1. Since then, at least 50 relevant papers on contaminants in marine fauna have been published. A comprehensive compilation and review of published data for contaminants in marine mammals, birds and turtles was recently undertaken2. An overview of this review will be presented, including key data gaps and recommendations for future research to improve our knowledge base of contaminants in marine megafauna and their use as a diagnostic tool for investigating wildlife strandings.