The 258 males and females who took part in the study represented more than 85 percent of all adjudicated and incarcerated juvenile delinquents in the State on that day. They completed questionnaires that gathered information about self-reported involvement in 22 delinquent activities, gang membership, associations with peers and adults, differential reinforcements, attitudes toward gangs, and personal characteristics. Results revealed that gang members had acquired more pro-gang attitudes than had nongang youths and were also more favorably inclined toward gang activities. However, neither gang membership nor the gang-based social learning theory variables were uniformly related to all forms of self-reported juvenile delinquency. Tables, footnotes, appended table, and 70 references (Author abstract modified)