Informal housing is a phenomenon usually related to the urban periphery of cities combining poverty andrapid growth, which are characteristic in Latin America and many other developing countries. This articleanalyses the phenomenon of informality in urban peripheries of the United States of America in generaland more specifically in Texas, where informal settlements known as colonias are inhabited by low-incomegroups that can’t find affordable alternatives within the formal housing offer available in nearby cities. Thearticle reflects on the role that new professionals of the disciplines of the built environment and other urbanstakeholders are to play in this new challenge.