BackgroundA significantly greater proportion of patients who die due to aspiration pneumonia were diagnosed with in-hospital aspiration pneumonia (19%). The incidence and major predictors are not known clearly, especially in Ethiopia.ObjectiveTo determine the incidence and predictors of aspiration pneumonia among adult traumatic brain injury patients at Felege Hiwot comprehensive specialized hospital, Bahir Dar, North west Ethiopia, in 2021.MethodsAn institution-based retrospective study was conducted from all admitted adult traumatic brain injury patients at Felege Hiwot comprehensive specialized hospital from January 1, 2015 to December 31, 2020 for 51 days of survival. Descriptive statistics, Kaplan–Meier survival curve log rank test, and the Cox proportional hazard regression model were used.ResultsA total of 396 adult patients diagnosed and admitted with traumatic brain injury in the past 5 years were included. Seventy patients (17.67%) developed aspiration pneumonia, providing an incidence rate of 32.39 (95% CI=25-62–40.94) per 1,000 person days of observation. Independent predictors were being referred for AHR (2.43; 95% CI=1.12–5.25), nasogastric tube insertion AHR (3.02; 95% CI=1.43–6.39), and baseline Glasgow coma scale <8 AHR (3.88; 95% CI=1.42–10.062).ConclusionHaving a nasogastric tube and low baseline Glasgow coma scale were significant predictors. This improves prehospital and hospital care during transportation and admission time.