The Drug Use Monitoring in Australia (DUMA) project provides police, policy-makers, criminal justice practitioners and other professionals with systematic empirical data on illegal drug use among people detained and brought to a police station or watchhouse at seven sites throughout Australia. The report provides an overview of detainees at each site, including self-reported drug use, prior criminal behaviour and treatment history. Trend data indicate that use of heroin has largely remained stable while codeine has increased; MDMA has increased while methylamphetamine has remained stable, and cannabis has declined, although it still remains the most commonly used drug.