Are referendum results binding?

Constitution (2005)

http://parliament.iq/manshurat/dastoreng.pdf

Article 126: […] Second: The fundamental principles mentioned in Section One and the rights and liberties mentioned in Section Two of the Constitution may not be amended except after two successive electoral terms, with the approval of two-thirds of the members of the Council of Representatives, the approval of the people in a general referendum, and the ratification by the President of the Republic within seven days.

As the law provides, the final decision depends upon the ratification by the President.