Acute subdural haematoma (ASDH) is one of the conditions most strongly associated with severe brain injury. Reports prior to 1980 describe overall mortality rates for acute subdural haematomas (SDH's) ranging from 40% to 90% with poor outcomes observed in all age groups. Recently, improved results have been reported with rapid diagnosis and surgical treatment. The elderly are predisposed to bleeding due to normal cerebral atrophy related to aging, stretching the bridging veins from the dura. Prognosis in ASDH is associated with age, time from injury to treatment, presence of pupillary abnormalities, Glasgow Coma Score (GCS) or motor score on admission, immediate coma or lucid interval, computerized tomography findings (haematoma volume, degree of midline shift, associated intradural lesion, compression of basal cisterns), post-operative intracranial pressure and type of surgery. Advancing age is known to be a determinant of outcome in head injury. We present the results of a retrospective study carried out in Beaumont Hospital, Dublin, Ireland's national neurosurgical centre. The aim of our study was to examine the impact of age on outcome in patients with ASDH following severe head injury. Only cases with acute subdural haematoma requiring surgical evacuation were recruited. Mortality was significantly higher in older patients (50% above 70 years, 25.6% between 40 and 70 years and 26% below 40 years). Overall poor outcome (defined as Glasgow outcome scores 3-5) was also higher in older patients; 74.1% above 70 years, 48% between 40 and 70 years and 30% below 40 years. Poor outcome in traumatic acute subdural haematoma is higher in elderly patients even after surgical intervention.