The high prevalence of interrelated problems with opioid use disorder, injection drug use (IDU), and HIV/AIDS in Malaysia has led to the scale-up of public health approaches, including opioid agonist maintenance treatment with buprenorphine or methadone. Malaysia has more than 300,000 registered people who use drugs (PWUD)-approximately 1.1% of its population of about 30 million-and an estimated 170,000 people who inject drugs (PWID; Nazar and Ahlam, 2007; Global AIDS Response, 2012), with heroin continuing to be the drug most frequently injected. (Source: Drug and Alcohol Dependence)