Background: The Laryngeal Tube Suction II (LTSII; VBM, Medizintechnik, Sulz, Germany) is a recent revision of the Laryngeal Tube Suction. This study compared insertion and ventilation profiles of the LTSII and the ProSeal™ Laryngeal Mask Airway (PLMA™; Laryngeal Mask Company, Henley-on-Thames, United Kingdom) in anesthetized and paralyzed patients. Methods: One hundred adult male patients were randomly allocated to an LTSII or PLMA™ group. The rate of successful insertion, insertion time, airway leak pressure at a cuff pressure of 60 cm H2O, tidal volume during pressure-controlled ventilation, incidence of gas leakage with cuff pressure reduced and with the shaft inclined, position of LTSII under fluoroscopic observation, and postoperative airway morbidity were determined. Results: Insertion was successful in 37 and 48 of 50 patients with LTSII and PLMA™, respectively (P = 0.002), with similar insertion times. Tidal volume was lower with LTSII than with PLMA™. Median airway leak pressures of LTSII and PLMA™ were 16 and 21 cm H2O, respectively (P = 0.006). Gas leakage around the cuff was observed more frequently with LTSII than with PLMA™ when the cuff pressure was reduced or the shaft of the device inclined. The position of LTSII varied significantly and did not statistically correlate with patient height. Postoperative airway-related morbidity was not significantly different. Finally, tracheal misplacement of LTSII occurred in 5 of 50 patients (10%), but ventilation was possible in 4 of them, and misplacement was identified only after fluoroscopic examination was performed. Conclusion: Airway management with LTSII is inferior to that with PLMA™. Copyright © 2008 The American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.