This article examines how undocumented immigrants become politicized and evolved into a relatively powerful group in the United States. It does so by examining the evolution of day laborers from their humble beginnings in a Los Angeles suburb in the early 1990s into an important component of the national immigrant rights movement today. It addresses the issue by examining the strategic importance of the ‘urban' in enabling stigmatized individuals like undocumented day laborers to overcome major barriers and establish themselves as a vocal and potent group in the public sphere. It suggests that once this group gained a foothold and a sense of itself through urban relational spaces, it experienced enhanced capacities to make rights claims in local and national political arenas. The article uses a case study of immigrant activism in Pasadena and Los Angeles, California, and draws special attention to the evolution of the National Day Labor Organizing Network (NDLON).