Tracheal intubation can be done in paediatric patients after induction of anesthesia with sevoflurane without muscle relaxant. Forty ASA physical status I-II patients, aged 1-10 yr and weight 10-25 kg scheduled for surgery under general anesthesia in Ramathibodi hospital were randomly assigned into two groups using 4% sevoflurane (group 1) and 8% sevoflurane (group 2). After gas induction, tracheal intubation was attempted without muscle relaxant. The intubation time (from loss of eyelash reflex to intubation) was predetermined by the up-and-down method (with 30 seconds as a step size) for each patient and started at 4 minutes for the first patient in each group.  Intubation time in 4% sevoflurane group (2.98 ± 0.42 minutes) is significantly different from 8% sevoflurane group (1.34 ±0.49 minutes). There were no significant hemodynamic change and desaturation in both groups.We conclude that tracheal intubation can be performed faster with 8% sevoflurane in N2O/O2 than 4% sevoflurane in N2O/O2 without adverse hemodynamic effect.