Thousands of Mexican and Central American migrants converge at the Mexico-United States border. Undocumented migrants in transit to the United States are vulnerable due to their lack of access to health care and legal assistance. This study attempts to provide evidence on the violent-related consequences that migration has on migrants. A mixed-method study was conducted between April 2006-May 2007 in shelters in Baja California, Mexicali and Tijuana, Mexico. 22 in depth interviews were performed and fifteen hundred and twelve migrants responded a questionnaire. Results from both in-depth interviews and the analysis of the quantitative data shows the different types of violence experiences by migrants which include threats, verbal abuse, and arbitrary detention based on ethnicity, as well as assaults, beatings and sexual violence. It is crucial to stress the importance and the need to evidence the condition in which migrants’ transit to the US and to effectively respond to the violence they experience.