The carrying capacity of pure pastoralist livelihood strategies only to attain food and livelihood security is extremely declining from time to time. Diversifying livelihood strategies at current time become a standard phenomenon within the study area. The general objectives of this study are, therefore, to characterize the existing livelihood strategies adopted by pastoral households and its determinants in the Sawena district, Oromia National Regional State, Southeast Ethiopia. To examine this general objective, the study employed descriptive statistics and bivariate probit model. Both primary and secondary data sources were used for the study. For the purpose of this study primary data collected from 350 sample households through face-to-face interviews. In addition, focus group discussions and personal observation are used. Relevant secondary data were also obtained from concerned zonal and district government offices. Descriptive statistics was applied to characterize livelihood strategies of the sample households. The finding of the survey result indicates that about 66.57% of households engaged on pure pastoralist activities, whereas about 33.43% were relying only on agro pastoralist activities to achieve their livelihood goal(s). This result indicates that most of the pastoral household heads are engaged in pure pastoralist activities rather than diversifying toward agro pastoral and related non-pastoral livelihood activities. Bivariate probit model applied to investigate factors influencing the households’ choice of livelihood strategies. The Econometric model result indicated that age, family size, dependency ratio, tropical livestock unit of holding, access to mass media, distance from the nearest market, access to rural electrification, access to irrigation, total farmland size and access to rangeland were determining pastorals’ choice of livelihood strategies. The results of this study suggest that development interventions, policies and capacity-building activities should be designed to suit the felt needs and circumstances of different groups of pastorals households.