Posttraumatic adrenal hemorrhage is a frequent finding after severe abdominal trauma and can have important clinical implications if it is bilateral. With the increased use of helical CT in the evaluation of trauma patients, posttraumatic adrenal hematoma is more frequently diagnosed. We present the CT findings of a unilateral posttraumatic adrenal hemorrhage where the diagnostic findings only appeared in the follow-up study. We think that mild enlargement of the adrenal gland in a trauma patient can be an early sign of an impending adrenal hemorrhage.