Among baboon species, Papio anubis is the most broadly distributed species, ranging through most of central sub-Saharan of Africa. Papio anubis live in troops but the size varies in different area. There are three troops of P. anubis in Trigni forest with 149 to 180 members in each troop. The objective was to assess the abundance of Anubis baboon (AB) and their conflict with humans with respect to the livelihood of local farmers in Trigni forest of Gida Ayana district, Western Ethiopia. Counting was conducted early morning at 6:00 to 7:00 am and late afternoon at 5:00 to 6:00 pm when the baboons were at the site of their sleeping. Six trained data collators were arranged during census of AB. These six data collators were divided into three sites (Harawa, Gendo, and Kotam cliffs). To increase accuracy and minimize error, counting was also done when the baboons left their sleeping site and went to foraging area, and in the afternoon when AB return to their sleeping site. Population count was carried out three times during each dry and wet season. For the human-anubis baboon conflict (HABC) assessment, participatory techniques were used. Data were analyzed using descriptive statistical methods, using SPSS version 20. The dry and wet populations of AB were 484 and 511, respectively. The distance of farmland from forest edge and problems of HABC were directly correlated. Results showed that AB is physically strong enough to attack livestock. About 62.9% of the respondents indicated that they lost their livestock by AB during 2015/2016. Most of the respondents reported that they rely on dogs and children to protect AB from raiding crops and this require time and energy. The majority (78.5%) of the respondents strongly agree that habitat disturbance is the main cause of HABC in the study area. More than 93.1% of the livelihood of local farmers of Gute Gudina kebele, adjacent to the forest reserve was affected by conflict between humans and AB. AB spent most of their time along the road and entered the agricultural fields. They can also attack and injure humans especially females and babies if provoked. Therefore, leaving sufficient buffer zones between crop productions and forest that allow free movements of AB and avoid high guarding investments (easy for guarding) is recommended.