Background: Road traffic accident is a collision among vehicles, between pedestrians and vehicles, between vehicles and animals, or between fixed obstacles and vehicles which leads to human fatal injury and premature death. Children are highly vulnerable for road traffic accident death. Yet, evidence is scarce concerning it in this study area. Objective: This study aimed to determine the magnitude of mortality and associated factors among road traffic accident victim children admitted in East and West Gojjam Zone Specialized Public Hospitals, Northwest, Ethiopia 2021. Methods: An institution based cross sectional study was conducted among 391 victim children using simple random sampling techniques from February 1st, 2021 to March 30th, 2021. The sample size was calculated by using a single population proportion formula and the data were collected retrospectively using a structured checklist. The data were checked for completeness, consistency, coded and entered into EPI Data version 3.1 then transferred to STATA version 14 statistical software for analysis. Bi variable and multivariable binary logistic regression analysis were conducted to identify the association between dependent and independent variables. Adjusted Odds ratio with 95% CI was used to measure strength of association and P- value ≤0.05 was considered as statistically significant. Result: The overall mortality was 10.7% (95%CI: 8- 14). Patients’ age within 1- 4 years (AOR (95%CI: 7(2.0 -24.6), urgent needed of blood transfusion (AOR(95%CI: 3.2(1.03-9.8)), Glasgow coma scale<8 (AOR(95%CI: 6.7(2.1-20.8)), surgery done (AOR(95%CI: 4.7(1.6-14.1)) and length of stay <5 days (AOR(95%CI: 4.7(1.6-13.3)) were significantly associated with mortality of road traffic accident victim children. Conclusion and Recommendation: The overall mortality was high compared with other countries finding. Being young age, urgent need of blood transfusion, Glasgow coma scale<8, undergo surgery and short length of stay were significantly associated with mortality of road traffic accident victim children. This study recommended to conduct further prospective study Keywords: Mortality, road traffic accident, children, hospital, Ethiopia