© 2020Objective: The aim of this study is to determine the effectiveness of coblation midline glossectomy for obstructive sleep apnea (OSA) when used as an isolated procedure. We also aim to compare the effect of this surgical procedure on supine and non-supine apnea. Materials and Methods: The medical records of patients who underwent isolated tongue base surgery as a part of step-wise surgeries between January 2014 and February 2019 are retrospectively reviewed. Pre-operative and post-operative Epworth sleepiness score (ESS), body mass index (BMI), and polysomnographic data, including the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), supine AHI, and non-supine AHI of the patients were compared. Results: The study included 29 patients (26 male and 3 female). AHI improved significantly, decreasing from 34.9 ± 20.9 to 25.8 ± 17.6. Supine AHI decreased from 62.55 ± 28.23 to 55.18 ± 31.67 post-operatively, but this decrease was not significant. Non-supine AHI decreased significantly from 22.49 ± 24.02 to 14.08 ± 17.46. ESS and ODI also improved significantly. Conclusion: Coblation midline glossectomy is an effective surgical procedure when applied solely, with a success rate of 52%. Non-supine apnea benefits to a greater degree than supine apnea from this surgical procedure.