This article seeks to provide migrant rights advocates with international legal arguments that can be used to address domestic human rights abuses when domestic law is inadequate and in violation of U.S. treaty obligations. It discusses applicable international law and suggests how these standards may be used to protect migrant workers. The article: describes the working conditions of undocumented migrants in the United States, highlighting recent violations of their human rights. It discusses Hoffman Plastics Compounds, Inc. v. National Labor Relations Board, 535 U.S. 137 (2002), which limited the rights of undocumented workers, and its aftermath and in which there were no briefs detailing relevant international legal obligations and binding treaty law that might have affected the outcome. This law and the methods for raising it in the United States are covered, with a specific focus on violations of the right to organize in order to be free from exploitative conditions, the right to equality before the law, and the right to legal recourse. [This article also appears as chapter 21 of Anne Bayefsky, ed., Human Rights and Refugees, Internally Displaced Persons and Migrant Workers: Essays in Memory of Joan Fitzpatrick and Arthur Helton, (Leiden; Boston: M. Nijhoff, c2006).]