International treaties are legal instruments that facilitate relations between nations. They have created rights and obligations between the signatory parties, encouraging and promoting cooperation and economic development. For their ratification and subsequent enactment within states and their incorporation into domestic legal sources, procedures are established in different ways. This paper focused on one: the ratification procedure by means of referendum by citizen initiative. In Ecuador, this procedure is regulated in article 420 of the Constitution. The aim of the research was to analyse this procedure. The focus of the analysis was theoretical and legal. The results led to the conclusion that we are faced with a constitutional procedure of direct democracy of enormous importance, due to the fact that citizens can empower themselves in public decisions traditionally centred on the state and political parties.