Over the last 15 years, Mexican drug organizations have replaced domestic producers as the main manufacturers and distributors of meth in the United States. While Mexican cartels produce the majority (around 90 percent) of meth used in the United States, around 80 percent of precursor chemicals used in Mexican meth come from China. Precursor chemicals are increasingly being shipped from China to Mexico and Central America, where they are manufactured into meth, transported across the southern border of the United States, and brought into southwestern states—Texas, Arizona, and California—before being shipped across the country. Despite international counternarcotic efforts, meth precursor manufacturers in China continue to thrive because the country’s vast chemical and pharmaceutical industries are weakly regulated and poorly monitored. This report examines the extent of China’s illicit chemical production and the effectiveness of U.S. and international efforts to reduce precursor chemical flows.