The research aims to compare the succession mechanism of Head of State of Indonesian democratic and Islamic systems. The research was conducted within normative legal research method which compares one legal resource with others. The results of research show that there are similarities and differences in succession of head of state between Indonesian democratic and Islamic system. The similarities were found in terms of people involvement, requirements in general and inaugurations while the differences were recorded in general fundamental principle, succession system, legal source, principles, specific requirements and technical inauguration. It is recommended that the succession of Head of State in Indonesian democratic system needs election reform because it has very high cost and unequal capacity of a person in determining the Head of State so it can be changed by indirect democracy system or by other effective systems. Meanwhile, succession in Islamic system requires standard rules and procedures which written as a reference to adjust the need of modern era. In addition, in Indonesia the existence of a comprehensive and just law is necessary to avoid conflict among people.