OBJECTIVE: To investigate the prevalence and risk factors for chronic abdominal pain after Roux-en-Y gastric bypass (RYGB) surgery. SUMMARY BACKGROUND DATA: Abdominal pain is a frequent postoperative complication after RYGB surgery. Even if there have been defined several long-term complications, the literature regarding patients with unexplained chronic abdominal pain is sparse. METHODS: A single-center register-based cohort study with inclusion of all patients who underwent RYGB surgery between 2010 and 2015. Data from multiple registries, medical records, and a questionnaire were used. Patients with chronic abdominal pain were defined as those using strong analgesics, diagnosed with chronic pain, or referred to a specialized pain clinic. Patients with severe self-reported abdominal pain were defined as those reporting abdominal pain more than 2 times weekly within the last month. RESULTS: A total of 787 patients were followed for a median of 63 months. The prevalence of postoperative chronic abdominal pain was 11% and the prevalence of severe self-reported abdominal pain was 21%. Preoperative use of strong analgesics was a risk factor for chronic abdominal pain (OR, 2.26; 95% CI, 1.59-3.23) and severe self-reported abdominal pain (OR 2.82, 95% CI 1.64-4.84). Further risk factors for severe self-reported pain were unemployment or retirement (OR 1.80, 95% CI 1.09-2.93), postoperative complications (OR 2.75, 95% CI 1.44-5.22), and smoking (OR 1.80, 95% CI 1.09-2.96). CONCLUSIONS: One in 10 patients undergoing RYGB surgery developed chronic abdominal pain requiring strong analgesics, and one in five suffered from severe abdominal pain. Risk factors were preoperative use of strong analgesics, unemployment, postoperative complications, and smoking.