This study comprises the Perth arm of a research project to monitor illicit drug use trends in major cities across Australia which is being coordinated by NDARC. The Illicit Drug Reporting System (IDRS) provides a coordinated approach to the monitoring of data associated with illicit drug use in Australia. The information collected is intended to act as an early warning system of the availability and use of four main drug categories: heroin, amphetamines, cocaine and cannabis. The methods employed include qualitative interviews with injecting drug users, a qualitative study of key informants who work in the drug field (eg. health, law enforcement, outreach, and research professionals) and an examination of existing indicators (eg. survey data, health and police data).