Aim: In this study, we aimed to investigate the early effect of probiotic supplementation after Laparoscopic Sleeve Gastrectomy (LSG) on constipation and gastrointestinal quality of life compared to control group. Methods: This study was a prospective, randomized clinical trial. Participants were recruited to Bariatriklab Obesity and Metabolic Surgery Center for LSG. All patients were divided into 2 groups as probiotic and control by using simple randomization. The probiotic group consumed Bifidobacterium animalis lactis BB-12 strain as a probiotic supplement during 6 weeks after LSG. Gastrointestinal Symptom Rating Scale (GSRS), Constipation Severity Instrument (CSI), Patient Assessment of Constipation Quality of Life Scale (PAC-QOL), Bristol Stool Form Scale (BSFS), Gastrointestinal Quality of Life Index (GIQLI) of the patients were recorded before LSG and at the 2nd, 4th, 6th weeks after LSG. Results: The probiotic group had an average age of 37.00±8.92 years (18 female, 12 male), the control group had an average age of 41.03±11.29 years (23 female, 7 male). CSI (16.50 ± 14.76 vs. 31.37 ± 15.34), PAC-QOL (58.53 ± 12.59 vs 72.30 ± 19.70), GSRS (26.83 ± 9.14 vs. 37.93 ± 16.59) and total score mean were lower compared to the control group, GIQLI total score average (147.50 ± 11.79 vs 136.87 ± 18.98) was found higher (p <0.05) in probiotic group. Conclusions: Probiotic supplementationimproved the constipation and gastrointestinal quality of life in the early post LSG-period in the brobiotic group compared to the control group.