Patients with poor grade aneurysmal subarachnoid haemorrhage (SAH) are associated with high mortality and morbidity, and hence are often treated conservatively. This study has set out to determine the outcome for all poor grade subarachnoid haemorrhage patients, and attempts to identify a subgroup with a more favourable prognosis. During a prospective audit of patients with aneurysmal SAH, patients of poor grade [World Federation of Neurological Surgeons (WFNS) IV (and not obeying commands) and V] were sedated, paralysed and ventilated for transfer to the Regional Neurosurgical Unit. Any intraventricular blood and/or hydrocephalus was treated by external ventricular drainage. Following a 24-h period for active blood gas, fluid and electrolyte resuscitation, patients were assessed after reversal of sedation. Selection for angiography and potential aneurysm surgery was restricted to those who showed a purposeful response to painful stimulation. Patients who could readily obey commands were not considered 'true' poor grade and were excluded from analysis. In 102 patients with 'true' poor grade SAH admitted between 1991 and 1997, the overall management outcome at 6 months was poor (favourable outcome 25%, mortality 67%). Following reversal of sedation, 55 patients demonstrated a purposeful response and proceeded to angiography, of whom 37 underwent clipping and three coiling of aneurysm. The outcome in this aneurysm treated subgroup was favourable in 53% (mortality 28%). If patients over the age of 65 years are excluded, the management outcome was favourable in 35% (mortality 58%), with those patients proceeding to clipping or coiling of aneurysms having a favourable outcome in 57% (mortality 27%). Patients over the age of 65 years with poor grade SAH had a favourable outcome in only 6% (mortality 85%). The mortality for poor grade SAH patients remains high. However, following resuscitation and correction of any acute hydrocephalus, a patient subgroup identified on simple clinical criteria can be identified who can expect a better outcome.