Following the end of the Cold War and the attacks of 11 September 2001, national definitions of security across the western hemisphere have been transformed. Whereas security was once narrowly defined, and often linked to the ideological containment of communism, the concept has expanded significantly to include issues ranging from narcotics-trafficking (hereafter narco-trafficking) and organized crime to corruption and weak rule of law. Security threats to states have become considerably complex, encompassing social and economic challenges at the root of the problem. It is not clear what new security strategies are needed in response to these complex challenges. States continue to adapt their domestic security structures as well as to seek greater multilateral security cooperation, but there is not yet consensus about the best way forward, and the challenges remain daunting. For example, Honduras has the highest murder rate in the world at 67 per 100 000 people, El Salvador has an estimated 30 000 gang members many of whom have been repatriated from the US (Shifter 2011: 53), and approximately 800–1000 tons of cocaine originate and are trafficked through the region annually (UNODC 2010). The scope of regional security challenges continues to grow and the national capacity to address it remains uncertain. The possible benefits of further multilateral cooperation are yet to be fully explored. In order to study and assess inter-American security developments within the context of the OAS, this chapter begins with a brief historical overview and then focuses on the nature of security challenges facing Latin American states today.