Objective:To evaluate the effect of gender factor on the potency of remimazolam inhibiting responses to laryngeal mask airway (LMA) insertion.Methods:Patients of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, aged 18-60 yr, with body mass index of 18-28 kg/m 2, requiring LAM insertion, undergoing elective surgery, were divided into 2 groups according to the gender: male group (group M) and female group (group F). The dose of remimazolam was determined by using modified Dixon′s up-and-down method.Remimazolam 0.3 mg/kg was injected intravenously in the first patient.When the patients lost consciousness, bispectral index value ≤60 or modified Observer′s Assessment of Alertness/Sedation score <1, sufentanil 0.3 μg/kg and rocuronium 0.6 mg/kg were injected intravenously, and the LMA was inserted 3 min later.The positive response to LMA insertion was defined as swallowing, biting LMA, bucking, body movement during insertion, or an increase in the maximum mean arterial pressure or the maximum heart rate >20% of the baseline value with 2 min after insertion.When the response to LMA insertion was positive or modified Observer′s Assessment of Alertness/Sedation score >1 after injection of remimazolam, the dose of remimazolam was increased in the next patient, otherwise the dose was decreased, and the difference between the two successive doses was 0.03 mg/kg.This process was repeated until the 7th turning point occurred.The median effective dose (ED 50) and 95% confidence interval (CI) of remimazolam inhibiting responses to LMA insertion were calculated by Probit. Results:A total of 29 cases in group F and 22 cases in group M completed the study.The ED 50 (95% CI) of remimazolam was 0.146 (0.106-0.175) mg/kg in group F. The ED 50 (95% CI) of remimazolam was 0.203 (0.131-0.237) mg/kg in group M. The ED 50 of remazolam was significantly higher in group M than in group F ( P<0.05). Conclusion:The potency of remimazolam inhibiting responses to LMA insertion is more effective in female patients than in male patients.