The study of migrant populations poses unique challenges owing to the mobility of these groups, which may further be complicated by their cultural, educational, and linguistic diversity and legal status. These barriers limit the usefulness of traditional survey sampling methods and routine public health surveillance systems. Given that nearly one in seven people in the world is a migrant, appropriate methodological approaches must be designed and implemented to capture health data from these populations. This effort is particularly important because migrants typically suffer disparities related to access to care, infectious diseases, occupational injuries, and outcomes for mental and other health conditions. This pathbreaking resource is the first of its kind to engage with the many unique issues that arise when studying migrant communities. It offers a comprehensive description of quantitative and qualitative methodologies to use when working with migrant populations. By providing information and practical tools, the authors fill existing gaps in research methods and enhance opportunities to address the health and social disparities migrant populations face in the United States and around the world.