Ankle sprain is one of the most commonly treated injuries of the lower extremity. The treatment depends on the severity of the injury and the time at which it occurred. The physician must rely on the history as related by the patient to determine the age of the injury. Magnetic resonance imaging has been proven to help determine the severity of the injury but has not been used to determine the age of the injury. The present study was conducted to identify the typical findings of acute and chronic ankle sprains as a means of dating an ankle sprain based on its appearance on magnetic resonance imaging.