BACKGROUND: Decisions made for anti-reflux surgery can be guided by both EndoFLIP™ measurement of lower esophageal sphincter (LES) distensibility index (DI) and esophageal manometric measurement of lower esophageal function, but the exact nature of their relationship to one another is unknown despite serving similar purposes. The purpose of this study is to evaluate the relationship between pre-operative LES basal mean pressure with esophageal manometry and intraoperative gastroesophageal DI using EndoFLIP™ following crural dissection to aid in informing surgeons' decision-making during anti-reflux surgery. METHODS: A retrospective chart review was conducted of patients with gastroesophageal reflux disease who underwent preoperative esophageal manometry evaluation and anti-reflux surgery with EndoFLIP™ intraoperatively between December 2020 and January 2024. Data collected included LES basal mean pressure from manometry and the logarithm of intraoperative EndoFLIP™ DI. Data analysis included descriptive statistics, Pearson's correlation coefficient, and independent sample t-tests. RESULTS: A total of 147 patients were included in the study. Mean LES basal pressure was 20.3, and median DI after crural dissection was 4.6. There was a significant but weak to non-existent inverse correlation between LES basal mean pressure following crural dissection and logDI (r = - 0.243, p = 0.005). Mean LES pressures were compared with findings of significant differences at DI 5, 5.5, 6, 6,5, 7, 7.5, and 8 (p < 0.05 for all), thus, none of the analyzed DI cut-points could definitively be used to inform operative decision-making. CONCLUSION: There is a significant but weak or non-existent inverse relationship between LES basal mean pressure measured on manometry and DI following crural dissection during anti-reflux surgery, but no specific DI can determine best fundoplication type of surgery based on LES pressures. Surgeons should take advantage of the distinct information gleaned from both manometry and EndoFLIP™, when possible, when planning and performing anti-reflux surgery.