Trypanosomosis is a protozoan disease, mostly transmitted by the tsetse fly, Glossina species, which causes severe disease of livestock in Ethiopia. The disease is also widespread across the globe especially in sub-Saharan African states. A cross-sectional study with the objectives of determining the prevalence of bovine trypanosomosis and assess the apparent densities of the disease vectors was conducted from October 2019 to July 2020 G.C in Jima Arjo district, east Wollega zone, Oromia regional state, Ethiopia. A parasitological study using conventional buffy coat technique was employed for the determination of prevalence of trypanosomosis and species was identified by Giemsa stain technique, while baited traps were used for the vector survey. The results of parasitological study revealed that the overall prevalence was 36 (8.2%) at 95% CI. From the total trypanosome positive animals 22 (5.0%), 8 (1.82%) and 6 (1.36%) of them harbor T. congolense, T. vivax, and T. brucei, respectively. Relatively higher prevalence (10.91%) was seen in animals with poor body condition than those with medium (7.38%) and good (5.55%), body condition though it is not statistically significant ( P > 0.05 ). Higher infection rate was observed in male 26 (12.26%) than female 10 (4.39%) due to male cattle more exposed to the tsetse fly area or early released from home for drought reason. Out of the total positive animals, only 12 of them were anemic on buffy coat test of sampled blood. This justifies that animal could be positive for trypanosomosis without showing clinical sign of anemia which is the dominant sign in this disease. A total of 2185 vectors trypanosomes were collected among which 1,569 were tsetse flies and 616 were other biting flies. The density of Glossina species was 15.1 fly/trap/day. Glossina morsitans submorsitans and G. tachnoides were the two dominant species of tsetse flies recorded from the area. The present study indicated that tsetse and non-tsetse fly-borne trypanosomosis is a leading bottle neck for production and health of animals in Jima Arjo districts and similar case was found throughout the country which necessitates a coordinated vector and parasite control in order to alleviate the problem of the disease.