Aims: To assess the safety and efficacy of duodenal-jejunal bypass liner (DJBL) implantation for 9 months or 12 months in patients with obesity and sub-optomally controlled type 2 diabetes (T2DM). Methods: Over 4.25 years DJBLs were implanted in 90 adult patients with obesity and sub-optimally controlled T2DM at a single centre in England. The liners remained in situ for up to 12 months and outcomes were monitored in a registry. Results: Of the 90 patients (BMI 41.5±7.1kg/m2, HbA1c 79.3±20 mmol/mol), 53% were insulin-treated. During DJBL treatment, there was no difference between the mean±SD fall in HbA1c at 9 months (20.5±18.8mmol/mol) vs. 12 months (20.5±19.4mmol/mol) (p=0.95). The mean±SD weight loss at 9 months (13.8±7.7kg) was 1.6±3.6kg less than that at 12 months (15.4±8.4kg) (p<0.001). By 12 months, 15.6% of patients had had early DJBL removal due to serious adverse events (SAEs), from which they all recovered. Of these SAEs, 43% would have been avoided by DJBL removal at 9 months. Conclusion: DJBL is effective in people with intractable diabesity. To reduce the incidence of SAEs, our data support reducing the recommended/conventional implantation period for DJBL from 12 months to 9 months.