목적: Sleep video fluoroscopy (SVF) is useful to assess dynamic pharyngeal obstruction in obstructive sleep apnea syndrome but it is conducted within several minutes of drug-induced sleep. This study aimed to evaluate the correlation between upper airway obstruction sites within short duration of drug-induced sleep and full overnight natural sleep. 방법:This study included patients who underwent both SVF during midazolam induced short (about 15 minutes) sleep and pharyngeal manometry (PM) during overnight polysomnography (PSG) from 2004 to 2007. PM measures percents of retropalatal and retroglossal obstruction events during respiratory distress events. On the otherhand, SVF measures the obstruction level during desaturation events. In SVF, obstruction levels are soft palate, tongue base and both levels. 결과:Among total 102 patients, there were 94 male and 15 female patients. The mean age was 44.2 10.4 years old. The mean percent of retroglossal obstruction events in PM was 30.5 30.0 %. In SVF, there were 57 patients with soft palatal level obstruction, 7 with tongue base level and 38 with both levels. SVF result had a weak correlation (R2 = 0.05, P = 0.035) with PM results while sex, age, body mass index and PSG parameters had no correlation. Among 45 cases of tongue base associated obstruction in SVF, 44 showed retroglossal obstruction events in PM. However, among 57 cases of soft palatal level obstruction, only 9 showed absolute retropalatal obstruction events. SVF had a low sensitivity 47.8% and high specificity 90.0%. 결론:Although SVF provides information of the obstruction sites, it weakly represents obstruction events during the overnight sleep. Especially, soft palatal level obstruction in SVF could not exclude retroglossal obstruction events in natural sleep.