INTRODUCTION: Esophagogastric junction (EGJ) outflow obstruction (EGJOO) per Chicago Classification v4.0 (CCv4.0) represents a high-resolution manometry (HRM) diagnosis with uncertain clinical significance. This study aimed to evaluate functional lumen imaging probe (FLIP) panometry among patients with EGJOO on HRM/CCv4.0 to assess clinical/manometric associations and treatment outcomes. METHODS: An observational cohort study was performed on patients who completed FLIP during endoscopy and had an HRM/CCv4.0 diagnosis of EGJOO, i.e., HRM-EGJOO (inconclusive). Abnormal FLIP panometry motility classifications were applied to identify FLIP-confirmed conclusive EGJOO. Rapid drink challenge on HRM and timed barium esophagram were also assessed. Clinical management plan was determined by treating physicians and assessed through chart review. Clinical outcome was defined using the Eckardt score (ES) during follow-up evaluation: ES < 3 was considered a good outcome. RESULTS: Of 139 adult patients with manometric EGJOO (inconclusive per CCv4.0), a treatment outcome ES was obtained in 55 after achalasia-type treatment (i.e., pneumatic dilation, peroral endoscopic myotomy, laparoscopic Heller myotomy, or botulinum toxin injection) and 36 patients after other nonachalasia-type treatment. Among patients with conclusive EGJOO by HRM-FLIP complementary impression, 77% (33/43) had a good outcome after achalasia-type treatment, whereas 0% (0/12) of patients had a good outcome after nonachalasia-type treatment. Of patients with normal EGJ opening on FLIP, one-third of patients treated with achalasia-type treatment had a good outcome, while 9 of the 10 treated conservatively had a good outcome. DISCUSSION: FLIP panometry provides a useful complement to clarify the clinical significance of an HRM/CCv4.0 EGJOO diagnosis and help direct management decisions.