ABSTRACT: This article examines the formation, determination, and quality of employment concentration for low-skilled Latino immigrants. Comparative evidence is drawn from the three metropolitan areas of Chicago, Los Angeles, and Washington, DC. Using 2000 Public Use Microdata Sample (PUMS), gender-specific ethnic niches where Latino immigrants disproportionately concentrate are identified and niche effects on wage earnings are analyzed. This study finds that while ethnic niches are evident in all three cities, they are most prevalent among women and newly arrived immigrants, and in the emerging gateway of Washington, D.C. Niche employment is almost uniformly characterized by earnings disadvantage as compared to non-niche employment, with lower returns premium on workers’ human capital and work experience, especially for men. Niche effects on earnings vary across metropolitan areas in accordance with their economic structure as well as with the size and profile of immigrants.