Objective:To investigate the impact of overweight/obesity on postoperative complications in breast reduction surgery.Methods:A retrospective study was conducted on patients who underwent breast reduction surgery in our hospital from 2016 to 2022. Basic patient information and postoperative complications, such as poor wound healing, infection, hematoma, nipple necrosis, etc., were collected. Patients were categorized into normal/low weight group and overweight/obese group according to their body mass index (BMI). The differences in postoperative complications between the two groups were compared and statistically analyzed.Results:The study included 82 patients, 48 in the normal/low weight group and 34 in the overweight/obese group. The gender, age, and surgical methods of the two groups of patients were relatively balanced, and there was no statistical difference. However, the incidence of postoperative complications was 50.0% (17/34) in overweight/obeseitg group, higher than 18.8% (9/48) in normal/low weight group. Common complications included delayed healing such as infection or dehiscence in 8 cases (9.8%), skin necrosis in 5 cases (6.1%), and hypertrophic scars in 5 cases (6.1%). The incidence of skin necrosis and delayed healing in the overweight/obese group was higher than that in the normal/low weight group, but the difference was not statistically significant ( P>0.05). Postoperative hematoma and hypertrophic scars occurred in both groups, while fat liquefaction and thrombosis only occurred in the overweight/obese group. Conclusions:Overweight/obesity is an important risk factor for postoperative complications in breast reduction surgery. Patients should be evaluated before surgery, and necessary measures should be taken to reduce the risk of complications.