The management of 40 intracranial aneurysms using profound hypothermia and cardiac arrest are reviewed. The technique is described and the reasons for using this procedure are discussed. It is suggested that this technique is of value in the treatment of giant aneurysms, aneurysms which could not be treated by conventional methods, multiple aneurysms, aneurysms in difficult sites and aneurysms complicated by other hazards, such as vascular anomalies.