Objective To examine the difference in the onset of and recovery from the neuro-muscular (N-M) blockade induced by rocuronium measured by acceleromyography of corrugator supercilli (CS) muscle and adductor pollicis (AP) muscle and the implication for clinical N-M monitoring. Methods Forty ASA Ⅰ - Ⅲ patients aged 32-65yr undergoing elective cholecystectomy or gastrectomy under combined general-epidural anesthesia (CGEA) were randomized to receive rocuronium 0.6 mg?kg-1 (group A, n = 20) or 0.9 mg?kg-1 (group B, n = 20) to facilitate tracheal intubation. Patients with N-M transmission disease, serious heart and lung disease or hepato-renal dysfunction were excluded. Epidural was performed at T8-9 or T9-10 . The level of epidural block was below T4. N-M blockade was measured by acceleromyography (TOF-WATCH SX Organon Teknika) of AP muscle at the thumb and CS muscle at the superciliary arch simultaneously. General anesthesia was induced with midazolam 0.05 mg ? kg-1 , propofol 2 mg ? kg-1 , fentanyl 3 ?g ? kg-1 and rocuronium 0.6 or 0.9 mg ? kg-1 . Tracheal intubation was performed at 80 % depression of T1 . The intubation condition (rated as excellent, good, medium, poor). The onset time (time from injection of rocuronium to maximal depression of T1) and the time of return to 25% and 75% of the control height of T1 were recorded and recovery index (RI) was calculated. Results The onset time of N-M block of CS muscle was (111?36)s at 0.6 mg?kg-1 and (74 ? 26)s at 0.9 mg?kg-1 and that of AP muscle was (106 ? 34) s (0.6 mg?kg-1 ) and (84?28) s (0.9 mg?kg-1 ) . The onset time produced by 0.9 mg?kg-1 was significantly shorter than that produced by 0.6 mg?kg-1 . At 0.6 mg?kg-1 80% depression of T1 of AP muscle was equal to 66% (52%-81 % ) depression of T1 of CS muscle and only 2 out of 10 patients showed good intubation condition. At 0.9 mg?kg-1 80% depression of T1 of AP muscle was epual to 89% (76%-93%) depression of T1 of CS muscle and all patients showed good intubation condition. The recovery of CS muscle from relaxation was faster than that of AP muscle. Conclusion There are differences in the onset of and recovery from the N-M blockade induced by rocuronium between CS and AP muscle. Monitoring N-M blockade of CS muscle is better for intubation.