Drug addiction is a complicated and endless problem faced around the world. It is estimated that around 39.5 million of the global population use drugs in 2021. In Malaysia, a total of 123,139 people were identified as drug addicts. It is estimated that for every 265 people, one will become a drug addict. Malaysia loses more than RM8.65 billion every year for prevention, drug enforcement, treatment, and rehabilitation. Contingency management intervention is an effectively proven intervention in treating drug addiction worldwide. This book aims to share the effectiveness of the approach in a compulsory drug treatment centre in Malaysia. It explores its effect on clients and helps improve treatment engagement and intrinsic motivation in drug treatment and rehabilitation settings.