Objectives: Our study aims to determine the frequency of progressive hemorrhagic injury as observed on the CT scan from the initial scan performed at the time of presentation to a subsequent one in the 12 hours after the initial scan. Study Design: The type of study is a prospective observational case series. Setting: At Tertiary Care Hospital in Karachi, Pakistan. Period: 3 months from June 2018 to August 2018. Materials & Methods: All patients over 18 years of age who presented to the Accident and Emergency Department of the hospital with traumatic brain injury and had a CT scan performed within four hours of the injury were included in the study. A predesigned proforma was used to note down patient findings. CT scan findings were classified as subdural hematoma (SDH), intraparenchymal contusion (IPC) extradural hematoma (EDH) and subarachnoid hemorrhage (SAH). A repeat CT scan was performed twelve hours after the initial CT scan. Data were analyzed using IBM SPSS version 20.0, mean and frequencies were calculated for continuous variables while frequencies and percentages were calculated for categorical variables. Results: Of the n= 110 patients in our study 79 were males and 31 were female, the mean age of the patients was 34.25 years. The Glasgow Coma Scale scores at the time of arrival were between thirteen and fifteen for n= 33 (30%) of the patients, between nine and twelve for n= 54 (49.09%) of the patients, less than and equal to eight for n= 23 (20.90%) of the patients. Subarachnoid hemorrhage was present in n= 32 (29.09%) patients, intraparenchymal hematoma was present in n= 42 (38.18%) of the patients, while subdural hematoma and epidural hematoma was present in n= 14 (12.72%) and n= 22 (20%) of the patients respectively. Progressive hemorrhagic injury was found in n= 66 (60%) of the patients, while in n= 11 (10%) of the patients there was resolution of the lesion and n= 33 (33%) of the patients showed no observable changes in the repeat CT scan. Finally, our results indicate that of the 110 patients in our study PHI was seen in n= 17 (53.12%) patients with SAH, n= 18 (81.81%) patients of EDH, n= 5 (35.71%) patients of SDH and n= 26 (61.90%) patients of IPC respectively. Conclusion: According to the results of our study PHI is observed in 60% of the patients with a traumatic brain injury observed within the initial 12 hours after injury, and epidural hematoma and intraparenchymal contusions had the highest incidences of PHI among all the different types of traumatic brain injuries.