Transnational Organized Crime (TOC) refers to those individuals and organizations that operate transnationally for obtaining power and monetary gains by illegal means. TOC includes drug trafficking, weapons smuggling, intellectual property theft, cybercrime, and human smuggling operations. TOC networks pose a growing threat to national and international security. These criminal networks often penetrate state institutions, especially law enforcement, resulting in weak governance and significant corruption. They threaten the respective economies and damage the world financial system. This paper provides an overview of the strategic and policy initiatives that the United States and international community have taken, including an assessment of the TOC threat. The overview is followed by the metrics developed to evaluate the relative magnitude and direction of the threat over a 5-year period. This paper concentrates on one aspect of TOC -- drug trafficking -- and provides metrics for that threat to the United States.