In recent years, the production and use of synthetic drugs has grown dramatically. The most significant synthetic drug threat is posed by MDMA and methamphetamine use. Part 1 provides an introduction to the report and identifies the Office of National Drug Control Policy and the Department of Justice as the co-chairs of the new Synthetic Drugs Interagency Working Group (SD-IWG), which will assume overarching responsibility for implementing the recommendations outlined in this report. Recommendations are then provided in the areas of prevention, treatment, regulation, and law enforcement. Part 2 offers an overview of the current consumption and trafficking trends with respect to synthetic drugs and diverted pharmaceuticals in the United States. Part 3 outlines the Federal Government’s plan of action to combat the problem of synthetic drug use and diverted pharmaceutical use. The recommended actions are grouped into the aforementioned categories of prevention, treatment, regulation, and law enforcement action. Current strategies being implemented in these areas are enumerated, followed by recommendations for future action. Recommendations include developing targeted prevention programs, increasing treatment capacity, and enhancing information exchange and coordination with Canada. Appendixes provide information about the proposed outline for an early warning and response system to address emerging drug threats; an overview of the new Drug Abuse Warning Network (DAWN) system; an action plan to prevent the diversion of OxyContin; the regulatory measures that apply to the drugs of interest in this report; and a summary of Missouri and Oklahoma precursor chemical control laws. The SD-IWG must submit a written implementation plan for the recommendations contained herein within 6 months of the publication of this action plan. Figures, appendixes, notes