Objectives: We conducted this study to evaluate the utility of the McGill oximetry score (MOS) to rule out moderate to severe obstructive sleep apnea syndrome (OSAS) in Korean children. Methods: We performed a cross-sectional study by using medical and polysomnography (PSG) records from our sleep disorder center. We assessed 58 PSG records conducted from September 2011 to December 2015. MOS was calculated from the overnight oximetry tests performed as part of PSG. We also investigated age, gender, height zscore, weight z-score, body mass index z-score, obesity, underweight, and pediatric daytime sleepiness scale. Results: MOS revealed inconclusive (score 1) in 50 (68.2%), and abnormal (2â4) in 8 (13.8%) of PSG results. And moderate to severe OSAS were diagnosed in 20 (34.5%) records according to the apnea-hyponea index (â¥5). In a multivariate logistic regression analysis, age [adjust odds ratio (OR) 0.8; p-value=0.013] and abnormal MOS (adjust OR 39.5; p-value=0.007) showed statistical significance between normal/mild OSAS group and moderate/severe OSAS group. MOS had a positive predictive value of 88%, a negative predictive value of 74%, a sensitivity of 35% and a specificity of 97% for detecting moderate/severe OSAS. Conclusions: In our small group study, MOS cannot exclude moderate to severe OSAS. Further prospective studies are needed. Keywords: Obstructive sleep apnea, Oximetry, Children