Introduction Alcohol overconsumption remains one of the adverse effects associated with bariatric surgery. Many previous studies have used subjective methods to evaluate the prevalence of alcohol overconsumption. In 2018, Örebro University Hospital started to use phosphatidylethanol 16:0/18:1 (PEth) as a screening tool pre- and postbariatric surgery. Research exploring alcohol use after bariatric surgery assessed with PEth is scarce. Aim The aim of this study is to evaluate the prevalence of alcohol overconsumption in bariatric surgery patients measured 2 years postoperatively with PEth and to identify possible risk factors associated with alcohol overconsumption. Methods This was a register-based retrospective, observational cohort study with PEth results collected from medical records at Örebro University Hospital. Patients who underwent bariatric surgery between January 2016 and June 2019 and who were registered in the Scandinavian Obesity Surgery Registry (SOReg) were included. Results PEth results from 410 bariatric surgery patients were identified. PEth values significantly increased from baseline to the postoperative follow-up (from 3.0% before surgery to 8.3% at the 2-year follow-up). In a univariate logistic regression analysis, the associated risk factors were found to be male sex (odds ratio, OR 2.14), older age (OR 1.06), and hypertension (OR 3.32). Conclusion The prevalence of alcohol overconsumption measured with PEth 2 years after bariatric surgery was 8.3% and was associated with male sex, older age, and hypertension. More studies are needed to validate the results of this study because it is not known whether PEth values are affected by bariatric surgery. Graphical abstract