Migration is undoubtedly one of the social phenomena with the greatest impact on the twenty-first century world stage. The number of people who for various reasons decide —or are forced— to move not only grows daily but becomes more complex. Some migrants, due to their numbers and impact, have a decisive influence on public policies and decision-making at the global, regional, national, and local levels. Migration of Mexicans to the U.S. has been, and continues to be, one of the most important and significant flows; hence, the importance for Mexico in general, and for the UNAM in particular, of hosting the 2015 International Metropolis Conference. Participants will include world-renowned specialists in the field. Also current immigration policy issues as well as academic studies seeking to understand and contribute to solving the problems arising from this phenomenon will be discussed.