A cross sectional study was carried out from December 2016 to March, 2017 in Bulen district of the Benishangul Gumuz Region, Western Ethiopia to determine prevalence of bovine trypanosomosis and associated risk factors. Blood samples collected from (n= 306) randomly sampled cattle (Bos indicus) was examined using parasitological (buffy coat technique) and hematological (measurement of packed cell volume) procedures. An overall, 18/306(5.88%) prevalence was recorded. The infection was caused mainly by Trypanosoma congolense 11/18(66.11%), Trypanosoma vivax 6/18(13.5%) and to less extent by Trypanosoma brucei 1/18(5.56%).The infection rate was statistically significant among difference trypanosome species (P<0.05). Mean packed cell volume (PCV) value of parasitaemic animals was lower (18.21% + 4.11) than aparasitaemic animals (28.12% +2.67) and the variation was statistically significant (P>0.05).Higher prevalence 11/82 (13.75%) was registered in animals with poor body condition animals when compared with animals medium 5/147(3.40%) and good 2/77(2.60%) body condition and the difference was found statistically significant (p<0.05). In contrast, prevalence of trypanosomosis was not statistically significant across study sites, among age categories and between sex groups (P> 0.05).To wrap up, the result of the present finding shows moderately high prevalence of trypanosomosis in the study sites indicating the need for strategic and integrated approach to control the vector and to minimize the impact of the disease in the study district.