BACKGROUND: As undergoing general anesthesia for Cesarean Section, we usually maintain a light anesthesia until delivery. It provokes the high incidence of waketulness for the mothers. We surveyed the incidence of maternal wakefulness when thiopental was used as an induction agent. METHODS: Forty pregnant women (ASA class I or II) at term who underwent general anesthesia and cesarean section received thiopental, 4mg/kg. As the 'isolated forearm technique', a pressure cuff was inflated to isolate one arm from the the effects of succinylcholine so that wakefulness during anesthesia could be assessed by asking the patient to move her hand. To assess wakefulness,the patient was commanded to squeeze the investigator's hand a specified number of times. If the patient promptly squeezed the investigator's hand the appropriate number of times, the command was repeated but a different number of times specified. Only if the patient responded correctly both times, then we noted as a positive response. This test was repeated at 1 minute intervals beginning 1 minute after thiopental injection through the delivery. RESULTS: Five of the forty patients (12.5%) showed wakefulness. Twenty nine of the forty patients showed 'reaching movements'. One patient showed both wakefulness and 'reaching movements'. CONCLUSIONS: When we undergo general anesthesia for Cesarean Section, especially using thiopental as an induction agent, we should consider the maternal wakefulness seriously.