Most of the data on which this analysis is based were collected in a service-research project in the control of gang delinquency. During the service aspect of the project, which lasted for 3 years, seven trained social workers maintained contact with 21 corner group units in a slum district of a large eastern city for periods that ranged from 10 to 30 months. Over 8,000 pages of direct observational data on behavior patterns of group members and other community residents were collected. Data include workers' contact reports, participant observation reports by the author (a cultural anthropologist), and direct tape recordings of group activities and discussions. Through an analysis of the data, the author determined that lower class culture manifests certain focal concerns: getting into trouble with the police, showing toughness, manifesting street smarts (outsmarting and conning others), experiencing excitement, being lucky, and maintaining freedom from constraint by authority figures. The focal concerns of the lower class juvenile street corner group reflect some of these class values. The concerns are belonging to a group and achieving status among peers. The customary activities of the juvenile street corner group include law violations that most often involve assault and theft. The primary thesis of this paper is that the dominant component of the motivation for delinquent behavior by lower class corner groups is an effort to achieve states, conditions, or qualities that are valued within the group member's most significant cultural milieu.