Hyoscine-N-butylbromide is used by some surgeons during laparoscopic sleeve gastrectomy (LSG) to loosen gastric smooth muscles and to provide a more effective LSG. However, evidence-based data on the effects of hyoscine-N-butylbromide in laparoscopic sleeve gastrectomy are limited and its effect on sleeve gastrectomy surgery and weight loss is unknown. The aim of this study was to analyze the effect of intraoperatively administered hyoscine-N-butylbromide on stomach resection volume, weight loss and complications seen in patients undergoing LSG. Patients who underwent laparoscopic sleeve gastrectomy due to morbid obesity were included in the study. Intraoperative hyoscine-N-butylbromide was administered to 52 patients (Group 1), not applied to the other 52 patients (Group 2). Age, sex, height, weight and body mass index (BMI) data of the patients were obtained retrospectively. The weight, BMI, percentage of total weight loss (TWL%) and percentage of excess weight loss (EWL%) of the patients were evaluated at postoperative third, sixth and 12th months. Resected gastric volume (p= 0.111), length of stapler line (p= 0.944), operation time (p= 0.383), hospitalization time (p= 0.494) and postoperative complications (p> 0.05) did not differ between Groups 1 and 2. However, frequency of intraoperative tachycardia (p <0.001) and hypotension (p= 0.006) in Group 1 was significantly higher than in Group 2. TWL% and EWL% values were similar between the two groups at all-time points. Stapler line leakage was not observed in any patient during the postoperative period. Intraoperative hyoscine-N-butylbromide use is not effective on weight loss postoperatively in patients undergoing LSG. Although hypotension and tachycardia occured in some of patients, none of the patients had complaints in the early or long-term postoperative period. The use of hyoscine-N-butylbromide during LSG is safe but does not have any effect on weight loss.