Background: Open fractures of the tibial diaphysis are caused by high energy trauma, most often from traffic accidents. It is also growing rapidly in developing countries. With rapidly increasing rates of motorization occurring in developing countries, knowing optimal treatment of open fractures of the tibial diaphysis is a global surgical priority. However, researches are limited in the field of orthopedic and traumatology in the study setting. Objective: To assess the outcome of open tibial shaft fractures treated with external fixation as the primary and definitive method in Tibebe Ghion Specialized Hospital, Bahir Dar, Ethiopia, 2020. Methods: A total of 53 patients (response rate of 88 %) with open tibial shaft fractures who were treated using external fixation at TGSH were retrospectively reviewed. Patients were interviewed and their charts were reviewed . Data was extracted, then entered and analyzed using SPSS, version 20. Descriptive analysis was used and summarized using frequency tables and charts. Binary logistic regression was also done to look for the association between independent factors and outcomes. Results: The average age was 34 ± 14 years, with Thirty six (67.9%) male and seventeen (32.1 %) female. The leading cause of the injuries was road traffic accident 19 (35.8%) followed by bullet , 15 (28.3 %) patients. Out of 53 patients included in the study, 34 (64 %) of them were having infection. Malunion and nonunion were found in 8 (15.1 % ) and 13 (24.5 %) patients respectively. Conclusion: Open tibial shaft fractures are majorly caused by RTA. Using External fixation for treatment of such fractures as a definitive one in our setup has lots of complications. Infection , nonunion and malunion rates are higher than other studies with significant reoperation frequency. use of external fixation for definitive treatment of open tibial shaft fractures isn’t reliable Keywords: Open fracture , tibia , External fixation , outcome