Traumatic brain injury is a leading cause of disability worldwide and most of them presenting to the hospital are those in the mild category. The current management of patients with mild traumatic brain injury varies amongst health centres across regions, due to lack of proper consensus and guidelines. In recognizing post traumatic amnesia duration as a predictor of the severity of mTBI, the Abbreviated Westmead Post Traumatic Amnesia Score (A-WPTAS) was created by Shores et al, 2008. The aim of this study was to validate the A-WPTAS to be used in the local setting and whether it can predict the optimal time of discharge of patients. This prospective cohort study was carried out in the Emergency Department of PPUKM for duration of 2 years beginning from 1st May 2013 which involved a total of 62 patients. Patients were observed and assessed using the A-WPTAS at hourly intervals for a minimum of 4 hours. All patients had a full A-WPTAS at 2 hours of observation. Patients who were fit for discharge were sent home and called back after 24 hours to determine whether they had any post concussive symptoms or not. Forty eight patients were discharged home well and did not report any post concussive symptoms after 24 hours. There were 7 (11.3%) patients who were admitted to the neurosurgery ward for abnormal CT scan results despite having a full AWPTAS score. Two (3.2%) of them had intracranial bleeds. However none of the patients required any surgical intervention. Although the safety and reliability of the A-WPTAS in the current setting remains inconclusive because of study limitations, it does show promise as an aiding tool for physicians to decide on patient discharge.