*Dong-Kyu Kim and Jung Woo Lee equally contributed to the work. Background and ObjectivesZZThe purpose of this study is to evaluate drug-induced sleep endoscopy (DISE) findings in patients with persistent obstructive sleep apnea (OSA) after uvulopalatopharyngoplasty (UPPP) surgery. Subjects and MethodZZPatients were included in this study if they had a postoperative DISE evaluation as well as preand postoperative polysomnography. DISE findings included the obstructive sites (velum, oropharyngeal lateral walls, tongue base, and epiglottis), and the obstructive patterns of velopharynx (anteroposterior, lateral, and concentric). ResultsZZA total of 77 patients were included in this study. Poor-responder patients to UPPP (n=50) and well-responder patients to UPPP (n=27) were similar with regard to age, gender, body mass index, preoperative AHI, and minimal O2 saturation. In our analysis of DISE findings on poor-responder, velopharynx was the most common obstruction site (100%), followed by oropharynx (88%), tongue base (70%), and epiglottis (44%). Results showed that most patients (n=49) had multiple obstructive sites. No significant differences according to position dependency and REM dependency were found in obstructive sites. However, severe OSA patients had tongue base obstruction more frequently than the moderate OSA patients did. The obstructive pattern of velopharynx usually showed concentric configuration (70%, 35 of 50). ConclusionZZOur results suggest that the preoperative DISE may be a useful method for determination of the personalized surgery to OSA patients because of its more precise information to upper airway obstruction. Korean J Otorhinolaryngol-Head Neck Surg 2014;57:96-102