Culturally and symbolically valuable ‘traditional’ institutions of Oromo people are coming to light through different studies. Complex and mysteriously organized Gadaa system, the Waaqeffanna religion, kinship structure, the adoption practices among others are the main focuses of recent academic and scholar discourses. This paper describes the role of the ‘traditional’ Gadaa systems, a uniquely social institution of the Borana Oromo people in Ethiopia, in the utilization of important natural resource management. The methodology was obtained essentially based on qualitative data consisting primary and secondary sources. The findings of this paper revealed that the ‘traditional’ Gadaa governance is performed for not only for political, religious, moral but also has role for natural resource management. The Borana and the Oromo protect a very wide variety of trees for different reasons which obtain from Gadaa Governance system. The most important one is the Sycamore (Fichus syscamores : odaa), symbolically associated with the qaalluu(the high priests of the society). Most Gadaa rituals are performed in the shade of a Sycamore tree. The tree and the surrounding area (ardaa jilaa) are fully protected. Other trees are protected because their wood is used to make ritual/cultural sticks and objects, because used in ritual or because of their positive association with grass grow and production of palatable fruits for man and livestock (Acacia: dhaddacha). This paper shows that, however there a growing need of Gadaa institution knowledge and wisdom in every aspect of Oromo life, over the years ‘traditional’ indigenous institution Gadaa have become weak and less effective in natural resource management because of land annexation, settlement, cultivation and the new government structure. The indigenous communal natural resource use and mutual assistance has also become ineffective. Resource use conflict in the area is frequent. Generally this paper explores Overview of the Horn of Africa and the Ethiopia Oromo Relationships, how indigenous institution (Gadaa) perceives their natural resource and manages to coexist in harmony with nature. This paper is not intended to be comprehensive. It is not directly concerned with the details of modern environmental ethics, but to describe the account of traditional indigenous institution of Gadaa Oromo towards the natural resource management particularly forest and water.