The Illicit Drug Reporting System (IDRS) serves as a strategic early-warning system for emerging trends and patterns in illicit drug use and associated harms. The IDRS has been conducted annually in every state and territory of Australia since 2000, and is supported by funding from the Australian Government Department of Health. The IDRS focuses primarily on four illicit drugs: heroin, amphetamines, cocaine, and cannabis but also monitors trends in other drug use and drug-related harms.