Aims: EndoBarrier is a 60cm duodenal-jejunal bypass liner endoscopically implanted for up to one year and designed to mimic the by-pass part of Roux-en-Y bariatric surgery. We aimed to assess the safety and efficacy of EndoBarrier in patients with suboptimally-controlled diabesity.Methods: Between July 2013 and November 2017 we implanted 90 EndoBarriers in a single centre with all removed by November 2018. Outcomes were monitored in a registry.Results: All 90 patients have completed one-year post EndoBarrier removal and, of these, 71/90 (79%) -age 51.3±8.6 years, 46% male, 52% White ethnicity, diabetes duration 13.0 (7.0-17.0) years, 59% insulin-treated, BMI 41.1±6.5kg/m 2 ) -attended follow-up and 19/90 (21%) did not attend follow-up. During EndoBarrier implantation, mean±SD HbA1c fell by 19.5±18.4mmol/mol from 78.1±18.9 to 58.6±13.6mmol/mol (p<0.001), weight by 15.9±8.6kg from 118.4±27.0 to 102.4±27.7kg (p<0.001), systolic BP from 139.0±15.0mmHg to 126.6±17.6mmHg (p<0.001), cholesterol from 4.8±1.2 to 4.0±1.0mmol/L (p<0.001), and serum alanine-aminotransferase (marker of liver fat) from 31.0±16.5 to 19.8±11.5U/L (p<0.001). Median (IQR) total daily insulin dose reduced from 98 (53-163) to 30 (0-63 ) units (p<0.001). Eleven of 42 (26.2%) insulin treated patients discontinued insulin. One year post-EndoBarrier 32/71 (45%) demonstrated fully-sustained improvement, 25/71 (35%) partially-sustained improvement and 14/71 (20%) reverted to baseline. Of those deteriorating, 10/14 (71%) had depression and/or bereavement. Thirteen of 90 (14%) patients required early EndoBarrier removal: five for gastrointestinal haemorrhage, two for liver abscess, one for non-hepatic intra-abdominal abscess, and five for gastrointestinal symptoms. All made a full recovery.Conclusion: Our data demonstrate EndoBarrier as highly effective in patients with refractory diabesity, with maintenance of significant improvement one year after removal in 80% of cases. As it requires only an endoscopic procedure, EndoBarrier treatment is relatively simple and non-invasive and it deserves further investigation.