Gangs have become a fixture in the Mexican American populations of southern California and other regions, spreading from low-income neighborhoods in the Southwest to working class and lower-middle class suburban areas. The development and institutionalization of gangs have involved many factors, including racial discrimination and economic barriers faced by Mexican American immigrants and their children; immigrant parents' loss of control over their children during the struggle to adapt to urban American culture; and the inability or unwillingness of other social institutions to meet these children's needs. The sense of displacement, isolation, and alienation that such Mexican American youth feel is associated with a condition of multiple marginality (with ecological, economic, sociocultural, and sociopsychological components). What began as wayward kids hanging around the street, almost detached from family influences, unfamiliar with and uncommitted to schools, and in fear of the law, gradually became rooted as a new subculture: the street gang. Gang subculture now dominates the streets, demanding adjustment and conformity from street socialized youth, but also providing a substitute caring, teaching, and sanctioning influence. Integral to this shift in the socialization process from the home to the streets are the effects of culture shock and conflict, leading to fragmented cultural adaptation and a "cholo" (mixed Mexican/Anglo) subculture. This digest discusses the development of a gang identity among adolescents; describes gang signs, symbols, and characteristic activities; and suggests that communities and schools adopt balanced intervention strategies. (SV)