We have compared the intubation conditions, durations of action, cardiovascular effects, side effects of bolus or intermittent administration of mivacurium. Forty ASA physical status I-II patients, undergoing elective surgery, were randomly allocated into two groups. Patients in (Group I); received a single dose of mivacurium (0.25 mg kg-1) in 60 sec and patients in Group II; received divided doses of mivacurium (0.15 mg kg-1 followed 30 seconds later by 0.1 mg kg-1). Induction was achieved with 5 mg kg-1 thiopentane and 2 μg kg-1 fentanyl. Anesthesia was maintained with 0.5-1.5% vol. of isoflurane and O2/N2O: (3/3 L min-1). Single twitch stimulation was used. Endotracheal intubation was performed when a twitch of 95% was blocked. Average onset times of the NMB, the duration of NMB (T1 25%, T1 75% recovery times, recovery of 25%-75%) were similar in both groups. There was no significant difference between the two groups. Total intubation conditions were good in Group II patients than Group I (p<0.05). We observed significant decreases in MAP before intubation in both mivacurium groups (p < 0.05). HR values were increased at the 2nd minute and decreased at the 15th minute in both groups (p<0.05). We observed increased airway pressure in two patients and ventricular arrhythmia in a patient in Group I. Increased airway pressure was determined by manometer. In conclusion; administration of divided dose of mivacurium may provide some advantage.