 Structural differences of supraglottic airway devices could influence the different compressive forces in the oropharyngeal cavities, and require different depth of anesthesia. The addition of remifentanil during propofol anesthesia facilitates the insertion of laryngeal mask airway LMA with minimal adverse hemodynamic disturbances. This study was designed to determine the effect-site concentration of remifentanil in 50 of patients EC50 and 95 of patients EC95 for successful i- gel insertion, and compare those for LMA insertion during propofol target-controlled infusion TCI. 