Introduction. ProSeal-Laryngeal Mask Airway™ (P-LMA™) is one of the commonly used laryngeal mask airways. Despite the proper insertion technique, suboptimal positioning and airway morbidity still occurs. This study explored the possibility of the operating table height position affecting successful P-LMA™ placement. Methods. A total of 138 patients aged between 18 and 65 years old with the American Society of Anesthesiologists (ASA) I or II status, who required general anaesthesia and had no contraindication towards the use of P-LMA™, were recruited. They were randomly positioned into three anatomical landmarks, which were umbilicus, lowest rib margin, and xiphoid. P-LMA™ was inserted following muscle paralysis, and the first successful placement was evaluated using positional and performance tests. Duration, ease of P-LMA™ insertion, and airway complications were compared. Results. Demographic and airway features were comparable among all groups. The P-LMA™ placement success rate improved when the table height was positioned at the lowest rib margin ( p = 0.002 ). All three positions were comparable in terms of duration, ease of insertion, and airway morbidities. Conclusion. The lowest rib margin anatomical landmark can be used as a guide in achieving the optimal operating table height for successful P-LMA™ placement.