Abstract: Objective To compare the efficacy of laparoscopic Roux-en-Y gastric bypass (LRYGB) and sleeve gastrectomy with transit bipartition (SG-TB) in the treatment of patients with obesity complicated by type 2 diabetes mellitus (T2DM).Methods The clinical data of patients with obesity and T2DM who were treated at the Affiliated Hospital of Xuzhou Medical University between February 2022 and December 2024 were retrospectively analyzed. According to the surgical procedure, the patients were divided into a LRYGB group (n=80) and a SG-TB group (n=87). Perioperative parameters, the preoperative incidence of gastroesophageal reflux disease (GERD), and the incidence of complications within 30 days after surgery were compared between the two groups. Obesity-related parameters, including body weight, waist circumference, hip circumference, body mass index (BMI), and percentage of excess weight loss (%EWL); glycemic parameters, including glycated hemoglobin (HbA1c), fasting blood glucose (FBG), and 2-hour postprandial glucose (2hPG); and lipid parameters, including high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC), were assessed before surgery and at 6 and 12 months after surgery.Results The SG-TB group had significantly shorter operative time, time to first flatus, time to oral intake, time to off-bed activity, and length of hospitalization stay than the LRYGB group, as well as significantly less intraoperative blood loss (all P<0.05). There were no significant differences between the two groups in the preoperative incidence of GERD or the incidences of anastomotic leakage, bleeding, and intestinal obstruction within 30 days after surgery (all P>0.05). However, the incidence of GERD within 30 days after surgery was significantly lower in the SG-TB group than in the LRYGB group (5.75% vs. 18.75%, P<0.05). No significant between-group effects or group-by-time interaction effects were observed for body weight, waist circumference, hip circumference, BMI, %EWL, glycemic parameters, or lipid parameters (all P>0.05). Compared with preoperative values, body weight, waist circumference, hip circumference, BMI, HbA1c, FBG, 2hPG, TC, TG, and LDL-C showed progressive decreases at 6 and 12 months after surgery in both groups, whereas %EWL and HDL-C showed progressive increases (all P<0.05).Conclusions Both LRYGB and SG-TB can effectively improve obesity-related anthropometric parameters, glycemic control, and lipid profiles in patients with obesity and T2DM, with favorable short-term safety profiles. Compared with LRYGB, SG-TB is associated with shorter operative time, earlier recovery of gastrointestinal function and ambulation, shorter hospitalization stay, less intraoperative blood loss, and a lower incidence of postoperative GERD.