ImportanceEvidence regarding the relative effectiveness of bariatric metabolic surgery (BMS) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) in reducing mortality and major adverse cardiovascular events (MACEs) is limited.ObjectiveTo compare all-cause mortality and nonfatal MACEs associated with BMS vs GLP-1RAs for adults with obesity and diabetes and without known cardiovascular disease.Design, Setting, and ParticipantsThis observational, retrospective cohort study was based on data obtained from the electronic medical records of Clalit Health Services (Clalit), the largest health care organization in Israel. The study included 6070 members aged 24 years or older, who had diabetes and obesity and no prior history of ischemic heart disease, ischemic stroke, or congestive heart failure. Patients who underwent BMS and patients who received GLP-1RAs from January 1, 2008, through December 31, 2021, were matched 1:1 by age, sex, and clinical characteristics. Follow-up ended December 31, 2022.ExposuresInitiation of BMS or GLP-1RAs.Main Outcomes and MeasuresThe primary outcome was all-cause mortality, assessed by multivariate Cox proportional hazards regression models. The secondary outcome was nonfatal MACEs, assessed by multivariate competing risk models.ResultsThe study included 3035 matched pairs of patients (total, 6070; mean [SD] age, 51.0 [9.5] years; 3938 women [64.9%]), who were followed up for a median of 6.8 years (IQR, 4.1-9.4 years). Among those with a diabetes duration of 10 years or less (2371 pairs), mortality was lower for those who underwent BMS than for those treated with GLP-1RAs (hazard ratio [HR], 0.38; 95% CI, 0.25-0.58). This association became nonsignificant when weight loss during the follow-up period was also included in the model (HR, 0.79; 95% CI, 0.43-1.48). Among patients with a duration of diabetes longer than 10 years (664 pairs), no survival advantage was demonstrated for BMS over GLP-1RA (HR, 0.65; 95% CI, 0.39-1.08). The risk for nonfatal MACEs did not differ between the treatment groups (HR, 0.74; 95% CI, 0.49-1.10 among patients with a diabetes duration of ≤10 years; HR, 1.21; 95% CI, 0.80-1.85 among patients with a diabetes duration of >10 years).Conclusions and RelevanceIn this cohort study, BMS was associated with greater reduced mortality compared with first-generation GLP-1RAs among individuals with a diabetes duration of 10 years or less, mediated via greater weight loss. No differences in the risk for mortality were observed between the treatment modalities among individuals with a longer duration of diabetes, nor in the occurrence of nonfatal MACEs among all patients.