Background: Staple line leakage after bariatric surgery can be treated by endoscopic placement of a self-expandable stent. The success rate of stent placement is generally high, but migration is a frequent adverse event that hampers successful treatment. The Niti-S Beta stent is a fully covered double-bump stent that was specifically designed to prevent migration. This study aimed to evaluate the effectiveness and adverse event rate of the Niti-S Beta stent. Methods: A retrospective study was performed in three high-volume bariatric centers. All consecutive patients between 2009 and 2016 who underwent placement of a Beta stent for staple line leakage were included. Primary outcome was resolution of the leakage; secondary outcome was the adverse event rate including migration. Results: Thirty-eight patients were included. Twenty-five (66%) had resolution of the leakage. Success rate was higher in patients who were treated with implantation of a Beta stent as initial treatment (100%) than in patients who were treated with a stent after revisional surgery had failed (55%, p = 0.013). Migration occurred in 12 patients (32%). There were two severe adverse events requiring surgical intervention, including a bleeding from an aorto-esophageal fistula. Conclusions: The success rate and the migration rate of the Beta stent seem comparable to other stents in this retrospective study. Despite the novel double-bump structure of the stent, the migration rate does not seem to be decreased.