War as intense armed conflict between states, governments, societies, or para groups, such as mercenaries, insurgents, etc is not old fashion but continues to be the vibrant and violet of society (ies). Many literatures relating to the war, Just war and just war theories pay attention mainly at the conflicts as a main cause of war but pass by about the cause of conflicts leading to the war. The objective of this paper is thus, to assess sources of conflicts leading (...) to the war, and come up with recommendation to narrow situations provoking conflicts leading to the war. Research approach employed was qualitative to qualify ideas and opinions of scholars, who conducted researches on war, just war and just war theories; books, journals and internet sources dedicated to the cause and consequences of war and sources concerned with the Jus Ad Bellum, Jus in Bello and Jus post Bellum have been reviewed. It was found that ambitions of humans to realize their unlimited natural rights, such as economic rights, political rights and extreme desire to un equitable utilization of such rights cause a war of “all against all”. The study recommends that authority better to avoid or reduce extent of conflict among humans, and humans to learn limit their unlimited natural rights for the sake of peace and security of the business. Key words: war, Just war theories, Jus Ad Bellum, Jus in Bello, Jus post bellum. -/- . (shrink)