Background: Laparoscopic sleeve gastrectomy (LSG) is one of the most prefered treatment option for morbid obesity. However, the effects of LSG on gastroesophageal reflux disease (GERD) are controversial. Asymptomatic GERD and hiatal hernia (HH) is common in obese patients. Therefore, it is important to identify the high risk patients prior to surgery. This study aims to evaluate efficacy of cruroplasty for HH during LSG in morbidly obese patients using ambulatory pH monitoring (APM) results, and to investigate the patients’ selection criteria for this procedure. Methods: This retrospective study includes outcomes of 59 patients who underwent LSG and HH repair according to our patient selection algorithm. Outcomes included preoperative GERD Health-Related Quality of Life (GERD-HRQL) questionnaire, APM results, percentage of postoperative excess weight loss, and total weight loss. Results: For a total of 402 patients, APM was applied in 70 patients who had a positive score of GERD-HRQL, and 59 patients underwent LSG and concomitant HH repair who had a DeMeester score of 14.7% or above. There was no statistically significant difference in weight loss at 6 and 12-month follow-up. Two patients (3.3%) had symptoms of GERD at 12 months postoperatively, and only one (1.6%) patient required treatment of proton pump inhibitor for reflux. In the total cohort, 11 (2.7%) patients also evolved de novo GERD symptoms. Conclusions: This study confirm that careful attention to patient selection and surgical technique can reduce the symptoms of GERD at short-term. Routine bilateral crus exploration could be a major risk factor of postoperative GERD.