This paper tries to discuss the effectiveness of US cooperation with Mexico in combating drug trafficking in the Merida Initiative policy from 2007 to 2012. The distribution of illegal narcotics in the two countries by the cartels has threatened the national security of each country because it has caused both losses in the form of threats to citizen killings during the circulation of narcotics were circulating. With this Merida Initiative cooperation policy, the Mexican government can reduce the circulation of narcotics to capture and kill the organized crime groups. However, every policy issued in the handling of narcotics has a side effect, namely the threat of violence and murder that is increasing not only by narcotics cartels but the Mexican government is also involved in acts of violence in implementing this narcotics eradication policy. Human rights violations to increased corruption contributed to a high number in the implementation of this policy. In completing this analysis, the author uses the theory of international cooperation and the concept of effectiveness to see how effective this collaboration is supported by several factors to solve the circulation of illegal narcotics