Computed tomography (CT) scanning is being increasingly used for evaluation of trauma, which most commonly involves younger individuals. As younger patients are at higher risk for radiation-induced cancer compared to older patients, radiation dose reduction is an important issue in emergency CT scanning. With automatic exposure control techniques, users select a desired image quality and the system adapts tube current to obtain the desired image quality with greater radiation dose efficiency. These techniques can help in reducing radiation dose by 10-60% in most instances. This review article presents a comprehensive description of fundamentals, clinical applications and radiation dose benefits of automatic exposure control in emergency CT scanning.