A cross-sectional and experimental study designs were conducted from September 2018 to March 2019 on cattle with the objective of determning the epidemiology of bovine trypanosomosis and trypanocidal drug efficacy trial in selected districts of Amhara Regional state, Tsetse infected areas of Northwest Ethiopia. A total of 602 blood sample were collected from indigenous zebu cattle of both sexes, all age group, all body conditioned and different coat colored animals by using simple random sampling methods from eight kebels in the studu area and examined using dark ground buffy coat technique and 41 cattle were found positive for trypanosomosis showing an overall prevalence of 6.81%. Of the total infected animals, 43.90%, 29.27% and 26.83% prevalence were caused by T. vivax, T. congolense and mixed infection (T.vivax and T.congolense) respectively. The prevalence of bovine trypanosomosis was statistically significant (p ≤ 0.05) with age of cattle and season of the year. The PCV values indicated that the overall mean PCV was significantly lower for parasitemic animals (20.95%) than apparasitemic animals (26.85%). Majorities of the respondent know the disease well and treat their animals themselves. Irrational use and free availability of drug in unauthorized shop and exposure of the drug for a long time result the problem of drug resistance. Twelve male indigenous zebu cattle aged 12 to 16 months were purchased from a trypanosome free area, infected with T. congolense isolates for trypanocidal drug efficacy trial. Treatment with diminazine diaceturate at 3.5mg/kg body weight of calf did not cure all the four infected calves but at the double dose of the initial with the same drug cure two of them while the remaining two calves relapsed the infection. Treatment with isometamidium chloride at 0.5mg/kg body weight of calf cure three of the calves but the remaining one calf relapse the infection. The relapsed calf retreated with the same drug at the double dose of the initial and cured from infection. The present study indicated that bovine trypanosomosis is the most important constraint of cattle production and there is development of drug resistance reflecting the need for strategic control measures of the disease; enforce regulatory measures for irrational use of drug and regular monitoring of trypanocidal efficacy for commercially available drug. Keywords: Bovine Trypanosomosis, Drug Efficacy, Jawi district, North Achefer district, Prevalence, Risk factors, South Achefer distric