In recent years, there has been growing concern about the negative impact on access to affordable medicines of international trade rules, including the World Trade Organization Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) and bilateral and regional free trade agreements containing "TRIPS-Plus" rights. These rules run counter to the human rights imperative to increase access to affordable medicines with deleterious impacts on individual and population health. In response, human rights and public health communities have employed impact assessments to provide decision makers with evidence of the potential effects of proposed laws and policies on individual and population well-being. In this article, we explore and contrast human rights and health impact assessments conducted in Thailand and Peru, respectively, during trade negotiations with the United States, to elucidate broader lessons for conducting human rights and health impact assessments in this arena.