Based on field studies conducted in the United States, five forms of ideal deviant organization can be defined according to associations, participation in deviant activities, division of labor, and whether the groups' activities extended over time and space. Loners do not associate with other deviants for any purposes, while colleagues have informational and social ties although they perform as individuals. Peers not only associate with one another, but also participate in deviance, whereas in mobs this shared participation requires an elaborate division of labor. Finally, formal organizations reach the highest level of complexity because their deviant undertakings also extended over time and space. In general, deviants in more sophisticated forms of organization commit more complex acts which require substantial resources and elaborate organization, as illustrated in the comparisons of an off-track betting operation, prostitution, and a mob's bank robbery. Loners with special resources, however, can commit complex crimes, as demonstrated by embezzlers and physicians. As a deviant organization increases in sophistication, socialization becomes elaborate, and newcomers may be recruited selectively by experienced members. More sophisticated organizations supply better services to their members, including specialized equipment and an intelligence system. Extended careers and close personal identity with the deviant group are characteristic of members in more sophisticated organizations. Career stability and monetary rewards offered by formal organizations attract a stable membership. While loners', colleagues', and peers' operations are insecure, mobs and formal organizations protect their members through physical security measures and a code of conduct regarding secrecy. Formal organizations can evade social control agents through members' loyalty, informational networks, corruption of public officials, and placing the lowest ranking members in positions vulnerable to arrest. Future research should consider the conditions under which a particular organizational form develops. For example, a large supply of customers is necessary to a gambling operation and nondeviant individuals may supply services to or support deviants. The article contains tables, 15 footnotes, and over 70 references.