Abstract Background: TBI is a worldwide health problem, which contributes to mortality and morbidity. Cardiac dysfunction has been reported after many neurologic injuries. Geriatric patients are more vulnerable to severe head trauma and developing acute coronary syndrome. Aim of Study: This study aimed to determine the incidence of acute coronary syndrome in elderly ICU patients with severe head trauma. Patients and Methods: This prospective cohort study was conducted on 47 elderly patients with isolated severe TBI, admitted to Emergency ICU Unit at Ain-Shams University Hospital. Heart rate and mean arterial blood pressure were monitored. Cardiac dysfunction was evaluated through studying ECG every 24 hours, serum cardiac troponin I on days 1 and 3, echocardiography after 12 hours of admission and on days 3, 5 and 7 and assessment of risk of mortality among patients with acute coronary syndrome by using GRACE score. Results: By the end of the study period, acute coronary syndrome was reported in 36.2% of patients with 10.6% mortality. GRACE score was significantly associated with patient mortality in those who developed ACS and had 100% sensitivity and 92% specificity in prediction of mortality among those patients at a cutoff value >19. Conclusion: Cardiac dysfunction is not uncommon in elderly isolated traumatic brain injury patients with increased in-hospital mortality.