The Borana rangeland has been an important area of cattle production in Ethiopia. Howeverrnrecent dominance by woody cover is considered as a threat to range conditions in the area. Arnmultidisciplinary approach was followed to assess impacts of bush encroachment on thernbiophysical environment and pastoralists’ livelihood in the two pastoralist associations and andrnto document pastoralists’ perceptions on bush encroachment. The rangelands were stratified intornencroached and non-encroached sites based on visual observation and data on vegetation andrnsoil parameters were collected from both encroached and non encroached sites. Pastoralists’rnperceptions were collected by informal interview. The data were analyzed using excellrnspeardsheet, PC-ORD, version 4.20 and SPSS (SPSS, 1989 – 96) version 14, computerrnprograms. Higher species diversity and herbaceous cover was observed in non-encroached site.rnIncrease in woody plant density might have limited survival rate and percent cover of some lightrnloving herbaceous species in encroached site. In both encroached and non-encroached lands arntotal of 94 plant species were identified, which included 26 woody and 68 herbaceous species.rnThe density of woody plant was greater than 2500 tree equivalent in encroached sites showingrnhigh threat of bush encroachment.Highly significant difference (p