Background/Aims: The Lyon Consensus defined parameters based on upper endoscopy and 24-hour combined multichannel intraluminal impedancepH (MII-pH), that conclusively establish the presence of gastroesophageal reflux disease (GERD). However, the true role of upper endoscopy and MII-pH to evaluate patients with extraesophageal symptoms (EES) has not been well established. Hypopharyngeal MII (HMII), which directly measures laryngopharyngeal reflux (LPR) events, has been utilized to evaluate patients with EES suggestive of LPR. Methods: This was a retrospective study involving patients with EES for > 12 weeks despite proton pump inhibitor therapy, and had no endoscopic confirmatory evidence for GERD and negative MII-pH. All patients were subsequently referred for further evaluation of EES with “unknown” etiology and underwent laryngoscopy and HMII. Based on HMII, abnormal proximal exposure (APE) was defined as LPR ≥ 1/day and/or full column reflux (reflux 2 cm distal to the upper esophageal sphincter) > 4/day. Patients with APE were offered antireflux surgery (ARS) and the outcome of ARS was objectively assessed using Reflux Symptom Index. Results: Of 21 patients with EES which was thought to be GERD-unrelated based on endoscopy and MII-pH, 17 patients (81%) had APE. Eight patients with APE who had undergone ARS had significant symptomatic improvement in the Reflux Symptom Index score (19.6 ± 4.9 pre-ARS to 5.8 ± 1.4 post-ARS, P = 0.008). Conclusions A conventional diagnostic approach using endoscopy and MII-pH may not be sufficient to evaluate patients with EES suggestive of LPR. HMII is essential to evaluate patients with EES, and APE could be a reliable indicator for successful treatment outcomes.