Forty obese patients with anticipated difficult airways were randomised to undergo awake orotracheal intubation by FOB(group F) or DE(group D) after conscious sedation. The conditions of orotracheal intubation, the time needed to view the vocal cords and to complete the orotracheal intubation, the hemodynamic changes and the adverse events including bradycardia, respiratory depression during orotracheal intubation, throat pain, hoarseness and memory after surgery were recorded. The ease of view the vocal cords and passing the tracheal tube through the glottis were also evaluated by using a visual analogue scale (VAS) by operator.