Examines the emerging structures of immigrant and refugee associations and organizations and the ways in which community-based groups accommodate the needs of immigrant constituencies. More than 30 million foreign-born people live in the United States, with the highest percentages residing in California, New York, Florida, and Texas. Yet, nearly every major city in the U.S. has an immigrant population. The 4 types of organizations that work in immigrant and refugee communities are: mutual assistance associations and ethnically based service providers, which are multicultural and multilingual and are geared to meeting the survival needs of new immigrants; traditional community organizing groups that respond to a changing demographic mix and which are able to integrate the concerns of established residents and new immigrants; immigrant rights organizations, which often work in collaboration with religious, labor, and other community groups; and crossover organizations, which combine expertise in a particular area such as economic development with deep knowledge of their immigrant constituents so as to fill specific needs not addressed by traditional organizations. Recommendations for strengthening the capacity of immigrant organizations include building alliances between immigrant and nonimmigrant communities and encouraging philanthropic organizations to fund multiple groups that serve the same constituency in different ways.