This thesis was written to explain why Indonesia and Malaysia had bilateral cooperation in transnational crime at in Kepulauan Riau. Indonesia as an archipelago of the country with a vast sea area has to fight the massive threat of drug trafficking. It is because the illegal drug trafficking syndicate is distributing their products by the sea route. One of their routes is Kepulauan Riau. This province is adjacent to Malaysia and faces Malacca Straits which is an international trade route. Therefore, Indonesian representatives, Polri, and Malaysia representatives, PDRM has to collaborate to eradicate drug trafficking using international agreements.