The objectives of this study were to determine how quickly patients who have an aneurysmal subarachnoid haemorrhage are diagnosed and referred to a regional neurosurgical unit for assessment and management. We examined whether delayed diagnosis resulted in poorer management outcome and how such delays could and should be avoided. An in-depth analysis of pre-hospital and hospital management of 180 consecutive patients with an aneurysmal subarachnoid haemorrhage was carried out at the Wessex Neurological Centre, a regional neuro-surgical unit with a catchment population of 2.8 million people. One hundred and eighty patients with a proven (computed tomography and/or lumbar puncture) aneurysmal subarachnoid haemorrhage were studied. The main outcome measures were management of mortality and morbidity using the Glasgow Outcome Scale (three months to one year follow-up period). Of the 180 patients, 136 were suitable for the study. Diagnosis was delayed in 69 (51%). In this group, failure to recognise this condition resulted in 45 patients (65%) suffering a second or third haemorrhage before being diagnosed. As a direct consequence of this delay significantly more patients died or were severely disabled than those whose haemorrhage was diagnosed without delay (chi 2 = 8.27, p < 0.005). Delays in diagnosis and transfer to a neurosurgical unit are largely avoidable.