Introduction: Decompressive craniectomy (DC) in severe traumatic brain injury (TBI) is controversial. The impact DC on cause of death is unclear in the literature to date. Methods: We performed an institutional retrospective review, from June 2003 to June 2013, of patients with severe blunt TBI undergoing DC whom subsequently died. We compared this group to a retrospectively matched cohort based: age, pre-hospital mRS, Marshall diffuse and TBI grades, Injury Severity Scores, and admission laboratory values. The goal was to determine the cause of death between those receiving DC and those managed medically. Results: Nineteen patients received DC and were compared to 16 retrospectively matched patients. The mean age of the DC and matched cohort were 47.1 and 43.6 years, respectively. The mean admission GCS/Marshall diffuse CT grades were 5.8/3.4 for the DC group, and 4.1/3.1 for the matched medical cohort. Overall, in the DC group 94.7% of the deaths occurred secondary to cardiac arrest after withdrawal of life sustaining treatment (WLST), with only 5.3% progressing to brain death. Alternatively, in the matched cohort 62.5% died of cardiac arrest post WLST, with 37.5% progressing to brain death. Conclusions: Progression to brain death appears to be more common in those severe blunt TBI patients treated medically compared to those undergoing DC.