Traumatic brain injury (TBI) is the commonest cause of death and disability in young adults living in industrialised countries. Recently, several studies have shown that hypopituitarism is a common complication of head trauma, with a prevalence of at least 25% among patients who were studied months or years following injury. This remarkably high frequency has changed the traditional concept of hypopituitarism being a rare complication of TBI, and suggests that most cases of posttraumatic hypopituitarism remain undiagnosed and untreated in clinical practice. It is therefore reasonable to infer that posttraumatic hypopituitarism may have an important contribution to the high physical and neuropsychiatric morbidity seen in patients with head injury. This article discusses the published reports on neuroendocrine dysfunction in TBI patients and the natural history of this disorder. The potential impact of posttraumatic hypopituitarism on recovery and rehabilitation after injury will also be examined, as well as the need for the identification, and appropriate and timely management of hormone deficiencies in order to reduce morbidity, aid recovery, and avoid the long-term complications of pituitary failure.