Background and aimsLiver cirrhosis is a complex disease that may result in increased morbidity and mortality following bariatric surgery (BS). The purpose of this study was to explore the outcome of BS in patients with unexpected cirrhosis, focusing on postoperative complications and the progression of liver disease. MethodsA retrospective study of bariatric patients with cirrhosis from four centers in China between 2016 and 2023 was conducted, with follow-up for one year after BS. The primary outcome was the safety of BS in patients with unexpected cirrhosis, while the secondary outcome was the metabolic efficacy of BS in this group postoperatively. ResultsA total of 47 patients met the study criteria, including 46 cases of Child-Pugh class A cirrhosis and 1 case of Child-Pugh B. Pathological examination confirmed nodular cirrhosis in 21 patients (44.68%), pseudolobule formation 1 patient (2.13%), lipedema degeneration with inflammatory cell infiltration in 3 patients (6.38%), and chronic hepatitis in 1 patient (2.13%). The average percentage total weight loss was 29.73±6.53% at one year postoperatively. During the 30-day postoperative period, the complication rate was 6.38%, which included portal vein thrombosis, gastrointestinal bleeding, and intra-abdominal infection. Moreover, no cases of liver decompensation or mortality were reported during the follow-up period. The remission rates of comorbidities among 41 patients one year after surgery were as follows: dyslipidemia 100%, type 2 diabetes 82.61%, hypertension 84.62%, and obstructive sleep apnea syndrome 85.71%. ConclusionBS can be safely performed in patients with unexpected cirrhosis in the compensated stage of liver disease, with low postoperative morbidity and no mortality observed during one-year follow-up.