Provides an empirical look at some of the principal new ethnicities being formed in the United States, based on results of the Children of Immigrants Longitudinal Study (CILS), a multifaceted investigation of the academic, social, cultural, and psychological adaptation of these children in southern California and southern Florida. The present second generation of children of immigrants in the United States is undergoing a process of assimilation that varies across minority groups. Both social scientists and professionals in the social services get information about: (1) the demographic diversity of immigrants and their children; (2) the unique challenges facing second-generation Mexican Americans; (3) the implications of living in an enclave for second-generation Cuban Americans; (4) attempts by Nicaraguan Americans to regain their collective voice; (5) the adaptive trajectories of the children of Filipino immigrants; (6) the acculturation of Vietnamese refugee children; (7) shifting identities and intergenerational conflict in Haitian families; and (8) the experiences of children of West Indian immigrants. The most effective policy in support of today’s second generation would consist of helping these children preserve a clear sense of their roots, the value of fluency in a second language, and self-esteem grounded on strong family and community bonds.