The document aims to provide an overview about the dual phenomenon of police´s militarization and the military´s police function in some countries. For this, a documental checking on the matter is makes, analyzing the cases of Germany, the United States, Mexico, Brazil, Chile and Colombia. The information reviewed suggests that the classical missionary division police and military forces is not happening in practice, due to internal factors driving public policy, the military organization of the police from its origins and changes in the conception of security and sovereignty of States.