This study examined induction and recovery times and respiratory and cardiovascular changes during induction and recovery in paediatric patients undergoing anaesthesia under spontaneous respiration induced with sevoflurane (S group, n= 10) and halothane (H group, n= 9) at 2.4 MAC. FET/FI increased more rapidly, the incidence of breath holding and coughing was less and the recovery time was shorter in the S group compared with the H group. During induction with sevoflurane at 2.4 MAC, min vol/bodyweight decreased due to reduced tidal vol/bodyweight despite increased respiratory frequency, as with halothane at the same MAC. Slight decrease in blood pressure was observed during induction in the S group, while the circulatory depression was not observed during induction in the H group. These results suggest that sevoflurane is a suitable agent for induction under spontaneous respiration with higher concentrations in paediatric anaesthesia.