Transnational Drug Trafficking Act of 2013 - Amends the Controlled Substances Import and Export Act to prohibit the manufacture or distribution of a controlled substance in schedule I or II, flunitrazepam, or a listed chemical by individuals having reasonable cause to believe that such substance or chemical will be unlawfully imported into the United States or into waters within 12 miles of the U.S. coast.
Prohibits the manufacture or distribution of a listed chemical: (1) intending or knowing that it will be used to manufacture a controlled substance; and (2) intending, knowing, or having reasonable cause to believe that the substance will be unlawfully imported into the United States.
Amends the federal criminal code to revise the prohibition against, and penalties for, intentionally trafficking in a counterfeit drug to apply to intentionally trafficking in a drug and knowingly using a counterfeit mark on or in connection with such drug.