The incidence of geriatric traumatic brain injury (TBI) is increasing throughout the United States, with many of these patients taking anticoagulation (AC) medication. The purpose of this investigation was to determine the effect of time to international normalized ratio (INR) reversal on intracranial hemorrhage evolution in TBI patients taking prehospital AC medication. We hypothesized that rapid reversal of INR improves outcomes of head-injured patients taking AC medication. Admissions to a Level II trauma center between February 2011 and December 2013 were reviewed. Patients presenting with an initial INR of 2.0 or more, computed tomographic scan positive for intracranial hemorrhage, and INR reversal to less than 1.5 in hospital were included. Patients with nontraumatic intracranial hemorrhage were excluded. Reversal of INR was achieved using some combination of fresh frozen plasma, prothrombin complex concentrate, and vitamin K. A binary logistic regression model assessed the adjusted impact of rapid INR reversal on intracranial hemorrhage evolution. Significance was defined as p < .05. One hundred subjects were included. Four patients with nontraumatic intracranial hemorrhage were excluded, resulting in a final study population of 96 patients. The most common intracranial hemorrhage in the study population was subarachnoid hemorrhage (71.9%), followed by subdural hemorrhage (35.4%). Reversal of INR of less than 5 hr was not associated with intracranial hemorrhage evolution; however, reversal of less than 10 hr was found to be associated with a decreased odds ratio for intracranial hemorrhage evolution (p = .043). Rapid reversal of elevated INR levels (<10 hr) may decrease intracranial hemorrhage evolution in TBI patients taking prehospital AC medication.