Objective: To evaluate the effects of sevoflurane on the dose-response relationship and on the timecourse of recovery of rocuronium. Method: Sixty patients,ASA grade Ⅰ,aged 18 to 52 years, undergoing elective plastic surgery,were included in this study. Patients were equally allocated randomly to either the control or the sevoflurane group. Anesthesia was maintained with 60％ N_2O-O_2-thiopental in the control group,and with 1 MAC sevofurane-N_2O-O_2 in the sevoflurane group. The dose-response relationship of rocuronium was established with a cumulative dosing regimen. Result: The dose response curve of rocuronium in the sevoflurane group was shifted to the left. The ED_(50),ED_(90) and ED_95 of rocuronium were decreased by 31％, 27％ and 25％, respectively in sevoflurane group as compared with those of the control group. Following an intravenous administration of rocuronium 400ug/kg,the duration of peak effect,duration of clinical relaxation,recovery index,and the total duration of action in the sevoflurane group were significantly prolonged vs. the control group. Conclusion: Sevoflurane can significantly enhance the neuromuscular blockade effect of rocuronium and prolong its duration of action.