Findings suggest that even low levels of gang organization are important for their influence on behavior; even incremental increases in gang organization are related to increased involvement in offending and victimization. When more evidence of gang organization was present, elevated levels of involvement in crime and victimization were observed. Gangs are not effective mechanisms for controlling drug sales, particularly at the retail level, and the degree of gang organization has little effect on participation in drug sales. This study used a seven item index of gang structure to construct an aggregate measure of gang organization that uses the key features of complex organizations, including: leaders, rules, and punishments for violating the rules, meetings, symbols of membership, responsibilities, and giving money to the gang. Whether current or former gang members were analyzed, significant positive relationships between the level of gang organization and involvement of the gang in violence and drug sales were found. Gangs are not very well organized and subsist clearly in the middle of the range of organizational complexity. Even the low level of organization of gangs reported important implications for the criminal behavior and victimization experiences of gang members. Policy implications from the research suggest that suppression and intervention efforts must pay more attention to the gangs that are the most organized, and responses to gangs on the part of police and social services agencies should be reconsidered. Interventions that reinforce the organizational structure of the gang are likely to produce negative consequences, particularly high levels of victimization and offending. Avoiding interventions whose latent or manifest function strengthens the organization of the gang must be paramount in any gang strategy. Steps that reduce the organization complexity of a gang will pay large dividends in reducing crime and victimization. Tables, notes, references