The data came from interviews with gang members, their peers, their relatives, criminal justice personnel, and public service personnel; participant observation in varied settings; and questionnaire-guided survey. Results showed that for youths whose early experiences with families and schools have left them with intense but confused personal needs, the barrio gang provides peer group functions that may be otherwise unavailable. The gang provides needed roles for asserting hyper-masculine behavior. It also gives youths a sense of protection and belonging, sometimes for the first time. Together these group functions promote the acquisition and affirmation of a self-identity. For some youths, the gang continues to be important throughout their young adult life, even up to and past 30 years of age. Thus, the urban gang helps their adolescent passage to adulthood. The gang must be understood as a group phenomenon that reflects varied individual inner needs, most of which are normal youth concerns that have been altered by the peculiar nature of barrio life. Notes and 42 references.