Today, many immigrant neighborhoods are plagued with poverty, inadequate schools, family disruption, single parenthood, teenage pregnancies, youth gangs, violent crimes, drug abuse and alcoholism, and anti-intellectual youth subcultures. Such unsettling environments put immigrant children of the inner city at greater risk than those living elsewhere. This brief reports on a study that focused on three immigrant neighborhoods in Los Angeles (Korean, Chinese, Latino) to examine ways in which neighborhood-based social structures influence immigrant children's after-school life by investigating types of social structures and differences by race/ethnicity; how these structures interact with one another to contribute to community-building, and types of social relations that the different structures foster. Fieldwork included pre-arranged one-on-one interviews with adolescents and adults with teenage children; random interviews with parents, local leaders, social workers and business owners' nonintrusive participant observations of structured activities and random gatherings; and participant observations with researchers doing volunteer work in selective publicly funded programs for children and parents, private after-school services, and cultural centers. Data from the U.S. census, California Department of Education and Los Angeles Unified School District were analyzed, as well as mainstream and ethnic media. Three demographic patterns were noted: racial makeup, nativity, and poverty. Public schools reflect these patterns. A wide range of retail businesses are found in the three neighborhoods, and all three also have various ethnically specific businesses and professional services. Formal organizations and institutions with specific programs serving children or youths exist in all three neighborhoods. The numbers and types of both nonprofit community-based organizations (CBOs) and the programs they offer do not vary drastically. Many depend primarily on public funds or on a combination of funds from various levels of government, private foundations, and individual or organizational donations. Although the functions and services of nonprofit CBOs are similar across ethnic neighborhoods, inequalities exist in the availability of private services oriented toward youths. The study found that children and adolescents who are involved in supervised after-school activities in their neighborhoods tend to do better in school, be more ambitious and articulate about their college plans and future careers, and have a clearer sense of purpose than those who are not so involved. Researchers postulate that the Asian-Latino difference in school performance and college preparation is largely due to the noted unequal access to neighborhood-based resources, such as privately run after-school activities. The study concludes that publicly funded school-based and community-based after-school programs are instrumental but insufficient in inner-city neighborhoods. Nonprofit and faith-based organizations have the experience and infrastructure to implement such support for immigrant families, yet they are largely under-funded and under-staffed. The role of ethnic entrepreneurship is critical for community building, as is the case of private supplementary educational establishments for facilitating the flow of information and enhancing intergenerational relations. The study recommends state action to: (1) provide multilingual educational materials to inform immigrant communities about college preparation and options; (2) encourage inter-group relations and coalitions by providing incentives to neighborhood businesses that provide services to more than one ethnic group, and allocating resources to building public-private partnerships; and (3) provide incentives to entrepreneurs to develop educational enrichment and other educationally related programs.