Background: Although the association between traumatic brain injury (TBI) and cardiac diseases were reported previously, the incidence of acute coronary syndrome (ACS) (per se) was not fully elucidated. The aim of this work was to estimate the incidence of ACS, associated factors and mortality during the first week of admission in patients with TBI admitted to intensive care unit (ICU). Patients and Methods: This retrospective study included all adult patients with TBI admitted to ICU (Al-Azhar University Hospital, Damietta), during (2016-2018). Patients with a history of cardiac co-morbidity, those who had associated chest, abdominal trauma, or bone fractures, were excluded. The collected data included: patient demographics, ICU clinical and laboratory data and history of chronic diseases. In additions, serum Troponin I, Glasco coma scale (GCS), electrocardiogram (ECG), echocardiographic examination, and patients' outcome were recorded. patients were divided into two groups according to the development of ACS the first included those who developed ACS and the second included those who did not develop ACS. Results: Of the 90 patients with TBI admitted to ICU, ACS was developed in (30.0%), age was (68.7±6.4), chronic diseases (40.7%). GCS was significantly lower in ACS group. Tachycardia, hypertension and hypernatremia was documented at admission. RBCs, hemoglobin and platelet count were significantly decreased while INR and PTT were elevated in ACS at admission and at 7th day. ECG changes in ACS group were in the form of ST elevation, ST depression and hyperacute T wave. Significant elevated troponin and abnormal echocardiographic findings were found in ACS group. Finally, significant increased mortality during the first week of admission in ACS compared to negative group (29.6% vs 3.2% respectively). Conclusions: These results documented the development of ACS after TBI and associated with older age, increased chronic disease, severity of trauma, hemodynamic instability, coagulopathy and increased ICU mortality. Search for ACS and identification of high‑risk patients after TBI are crucial to prevent cardiac morbidity and mortality. Otherwise, physicians could be exposed to medical negligence claims.