Transnational crime has been presented as an international phenomenon that affects all States and actors within the international system. The diversification and existence of different strategic points, routes and steps within the illegal processes have shielded transnational criminal gangs from justice and legality and have facilitated all viable and fruitful scenarios for illicit activities, This document reviews the main transnational crimes, their typifications, presents representative scenarios with emphasis on the countries of South America, which in a common denominator are characterized by being gray zones and by having long borders with weaknesses in security and defense.