The perioperative records of 354 consecutive patients undergoing craniotomy for surgical treatment of intractable epilepsy performed with conscious-sedation analgesia were reviewed retrospectively. There was no perioperative morbidity or mortality identified which could be attributed to the anaesthetic technique. The technique was not suitable for seven patients, in whom general anaesthesia was induced. The most frequent intraoperative problems were convulsions (16 per cent) and nausea and vomiting (eight per cent). Less frequent problems included excessive sedation (three per cent), "tight brain" (1.4 per cent) and local anaesthetic toxicity (two per cent). This study confirms that conscious-sedation analgesia provides suitable conditions for craniotomies when brain mapping is required.