Introduction:Sleeve gastrectomy is probably the most preferred morbid obesity surgery. It is important to provide patient comfort and early return to daily life after sleeve gastrectomy. Our aim was to investigate the effects of drain use on postoperative patient comfort. Materials and Methods:Fifty patients were randomly divided into two groups as no-drain and with-drain. The demographic characteristics and the intraoperative and postoperative findings of the patients were examined. Results:There were no differences between the two groups in terms of demographic data, intraoperative and postoperative findings except visual analog scale (VAS) scores. Two patients (8%) in no-drain group required drain placement. In the intention-to-treat analyses of the drain and the no-drain groups (25:25), the VAS values were 4.3 +/- 1.9 versus 3.9 +/- 2.1 (p = 0.48), 2.4 +/- 1.4 versus 2.4 +/- 1.6 (p = 0.98), and 1.8 +/- 1.5 versus 0.9 +/- 1.0 (p = 0.01) on the 1st, 2nd, and 3rd days, respectively. In the per-protocol analyses (27:23), the VAS scores on the first 3 days were 4.3 +/- 1.9 versus 3.9 +/- 2.1 (p = 0.78), 2.4 +/- 1.4 versus 2.4 +/- 1.6 (p = 0.98), and 1.8 +/- 1.4 versus 1.0 +/- 1.1 (p = 0.03), respectively. Conclusions:Routine abdominal drain use in sleeve gastrectomy negatively affects postoperative patient comfort by increasing pain. Randomized controlled trials are needed about the requirement of routine drain use in sleeve gastrectomy.ClinicalTrials.govID: NCT04333979.