BACKGROUND: A new laryngoscope, Flexiblade has flexible adjustable rigid blade. The Flexiblade is composed of a handle and a blade with an adjunct trigger. Squeezing the trigger changes the blade curvature from nearly a straight Miller blade into a curved Macintosh blade. This study was designed to evaluate the clinical application of the Flexiblade laryngoscope in endotracheal intubation for adult patients. METHODS: Following the induction of general anesthesia and muscle paralysis, the laryngoscopic views of 50 patients were measured while five different blade positions in the oral cavity were performed. The laryngoscopic view which was described by Cormack and Lehane was classified from grade 1 to grade 4 except one blade position. Adjusting maneuvers such as laryngeal lift and/or a styletted intubation were used to facilitate a tracheal intubation. Complications which were directly related to the Flexiblade laryngoscope were also evaluated. RESULTS: In use of the Flexiblade laryngoscope just like straight Miller blade, the vocal cord (< or =grade 2) were exposured in 82% of the patients. The 96% of patients showed a good vocal cord exposure (< or =grade 2) with a partial depression of the triggers of the laryngoscope. Overall rate of a successful intubation was 98%. In partial depression of trigger of the Flexiblade laryngoscope compared with neutral position, 22 patients of 26 patients with laryngoscopic view of grade 2 were improved by one grade, and 15 patients of the 17 patients with laryngoscopic view of grade 3 were improved by more than one grade. CONCLUSIONS: The Flexiblade laryngoscope is useful for endotracheal intubation for adult patients.