The study is aimed at investigating how livestock and human encroachments affect the population distribution and abundance of mountain nyala and Menelik’s bushbuck in Arsi Mountains National Park, Ethiopia. Across four dominant habitat types (Afro-alpine, Erica, natural forest, and mixed plantation forest) 5 × 20 (100 m2) plot was used to assess populations of the ungulates, wood harvesting, and livestock grazing through counting the fresh scats of both livestock and wild mammals and stumps of trees. There was significant negative correlation between the scat count of mountain nyala and livestock dung scat count during both dry (R=-0.518, p=0.031) and wet (R=-0.385, p=0.05) seasons. However, there was significant negative correlation between the scat count of Menelik’s bushbuck and livestock dung scat count only during dry season (R=-0.491, p=0.047). Season (wet versus dry) had significant effect on scat count of mountain nyala, Menelik’s bushbuck, and livestock. The study has clearly indicated that livestock outcompeted the endemic ungulates. Furthermore, the result of the study has indicated that tree removal reduced the wildlife habitat quality affecting the populations of wildlife. As a result, there is an urgent need for controlling the free-roaming domestic mammals, wood collection, and other human disturbances.