OBJECTIVE: To describe the long-term functional outcome of traumatic brain injury (TBI) patients treated by decompressive craniectomy (DC). METHOD: Data was collected on decompressive craniectomy performed on TBI patients admitted between May 1, 2018, and May 1, 2021, using a multi-centered, cross-sectional study design. The long-term outcomes of survivors were assessed using a structured extended Glasgow outcome scale (GOSE) questionnaire. Descriptive statistics, including frequency, mean, median, and range, were analyzed. Predictors of functional outcomes were determined using multivariate regression analyses. RESULT: In this study, 74 patients were examined and their mean age at the time of DC was 33.9 years, with a male-to-female ratio of 11:1. Primary DC was performed in 93.2% of cases, and the in-hospital mortality rate was 24.3%, while the overall mortality rate was 36.5%. Overall, a favorable functional outcome (GOSE ≥4) was witnessed in 43 patients (58.1%). Among survivors, 91.5% had favorable outcomes. Age ≥40, GCS ≤5, chest infections, and noninfectious complications were independent predictors of an unfavorable functional outcome (GOSE<
4). Patients with GCS ≤5 fared the worst with an unfavorable functional outcome rate of 85.7%. CONCLUSIONS: In this study, our results showed that significant number of our patients had favorable functional outcome after DC for TBI comparable to results from high income countries. We found that age, admission GCS, postoperative chest infection, and noninfectious complications were all independent factors predicting unfavorable functional outcome. In particular, patients with GCS ≤ 5 had a higher rate of mortality and unfavorable outcome.