No region of the United States is without youth gangs. Gangs exist in many large and middle-sized cities and are spreading to suburban and smaller communities. Youth gangs increasingly create problems in correctional and school settings. Compared with nongang offenders, gang members are responsible for a disproportionate percentage of serious and violent offenses and engage in the sale and distribution of drugs. Race or ethnicity and social isolation interact with poverty and community disorganization to account for much of the gang problem. The gang is an important social institution for low-income male youths and young adults from newcomer and residual populations, because it often provides social, cultural, and economic functions no longer adequately performed by the family, the school, and the labor market. Four major policies for addressing juvenile gangs have evolved: local community mobilization, youth outreach, the provision of social opportunities, and gang suppression. The most effective strategy integrates these approaches. The integrated strategy should be coordinated within a framework of social control and institution building. 1 figure, 247 references. (Author abstract modified)