Traumatic brain injury (TBI) is a leading cause of death and disability in the United States (US). The severity of a TBI is difficult to assess, and therefore, accurate determination of the prognosis is difficult. The symptoms of a TBI involve most major medical systems, and share many similarities with the symptoms of hypopituitarism. Although more than two-thirds of patients with severe head injuries who die have structural abnormalities in the hypothalamus and the pituitary, pituitary function is not routinely assessed after head trauma. Thus, studies have shown that anterior pituitary hormone deficiencies are common following brain injury [Endocrinologist 11 (2001) 275; J. Clin. Endocrinol. Metab. 86 (2001) 2752]. Survivors of brain injury should be screened for such deficiencies so that replacement therapy can be initiated to optimize rehabilitation and outcome.