The Illicit Drug Reporting System (IDRS) interviews are conducted annually with a sentinel group of people who regularly inject drugs, recruited from all capital cities of Australia (N=910 in 2018). The results from the IDRS interviews are not representative of all people who consume drugs, but this is not the aim of the study, instead intended to provide evidence indicative of emerging issues that warrant further monitoring. These results should be interpreted alongside analyses of other data sources for a more complete profile of emerging trends in illicit drug use, market features, and harms in Australia.