Highlights from the evaluation include: not including alcohol, 44 percent of interviewed detainees reported using two or more illegal drugs in the past 12 months, almost 30 percent had used two or more illegal drugs in the past 30 days, and 12 percent had used two or more illegal drugs in the 48 hours preceding their arrest. When alcohol is included, the rate of poly drug users increased to 63 for past year, 52 percent for past 30 days, and 26 percent for past 48 hours. The evaluation also found that most poly drug users used just two different drug types with a small percent reporting use of three or more different drug types. This report from the Australian Institute of Criminology (AIC) presents data for 2009 on the rate of poly drug use among police detainees. Data for the report were obtained from the AIC's Drug Use Monitoring in Australia (DUMA) program which collects information from police detainees at the time of their arrest. In 2009, the program survey 3,852 adult police detainees at 9 sites across the country. Information was obtained from the participants on their use of 10 different drug types at 4 different time points - ever, past 12 months, past 30 days, and past 48 hours. Information presented on the demographic differences of poly drug users shows that poly drug users are more likely to have had greater contact with the criminal justice system and more likely to be unemployed. The evaluation also found that the prevalence of poly drug use varied across the nine survey sites depending on how poly drug use was defined and calculated. Implications for policymakers are discussed. Tables, figures, and references