This study was carried out in pastoral areas Borena zone, Oromia Region of Ethiopia, are pure pastoralist the livelihood depends on livestock husbandry, with the main objective of investigating the customary pastoral land tenure practices effect on pasture land resource and livelihoods of the pastoral community and its implication to the need for pastoral land tenure reform. To address the stated objectives both primary and secondary data were collected from 291 sample size by using systematic random sampling methods, rural households living in five customarily defined pastureland designations lying in 5 Districts using questionnaire, focus group discussion, Key Informants and field observations. Analysis of the customary pasture land tenure and management in the study area revealed that the age old customary pasture land use practices are gradually eroded and equity of access is impaired due to the influence of economically strong pastoralists, and traditional management practices are being broken. Ranking of the major challenges in the pastoral areas indicated that recurrent drought stands first followed by land tenure insecurity, pasture land deterioration, and shortage of water. The study also revealed that the conflicts encountered in the pasture land use are mainly related to shortage of water and lack of grazing land. The problem is further exacerbated by attempts to enclose and privately use communal pasture and land alienation in the name of agricultural investment. About 75% of the respondents stated that conflicts are largely resolved by customary institutions. The decline in the productivity of the pasture land, and malpractices by the rich pastoralists, the declining authority of customary leaders and institutions as well as, the need for creating a well-defined boundary of the traditionally administered pasture territory and also the dire need for giving recognition of ownership of the pasture land to defined groups of pastoral communities seems triggering factors for introducing customary land tenure in the study area. It was also noted that the institutional arrangement to handle the customary land tenure did not take into account the value of the age old pasture land management. The findings of the study lead to conclude that customary pasture land tenure system is gradually eroded and attempts to introduce reforms in the land tenure are not supported by institutional arrangements that blend the customary leadership with more advanced systems. The distinctive livelihood feature of the pastoral community and its traditional attachment to customary land tenure demands to carry out a multidimensional and thorough investigations so that, stakeholders could