One type of environmental crime, the illegal harvesting and trafficking of wildlife, is a threat to the species, and the national economies and stability of nations dependent on this resource. Offenders committing this crime are often perceived as impoverished rural subsistence poachers seeking food or profit. However, criminal enterprises are very active participants in this offence. These range from established national and transnational organisations trafficking wildlife and other illegal commodities to small groups of limited duration organised to exploit an opportunity. What makes their involvement in this offence a serious threat is their ability to move large volumes of endangered wildlife products within and out of source nations to consumer countries, respond to changes in enforcement practices, and corrupt the institutions of government via bribery, extortion, and infiltration. This chapter examines the development, structure, and threats posed by transnational organised crime groups involved with the illicit wildlife trade in East and Southern Africa. Three examples from the region are provided to illustrate different aspects of the problem. The chapter concludes with recommendations to mitigate the threat.