Background <p>Long-term recurrent weight gain remains a persistent challenge in metabolic bariatric surgery (MBS). One strategy for managing recurrent weight gain involves the placement of a non-adjustable silicone ring around the reduced stomach pouch. This technique may lead to more significant weight loss and a reduced risk of long-term recurrent weight gain. Although several studies have demonstrated the effectiveness of silicone rings in combination with Roux-en-Y gastric bypass (RYGB), randomized studies providing long-term data on the effectiveness of primary banded one-anastomosis gastric bypass (OAGB) are lacking.</p> Methods <p>A total of 210 patients will be included in this prospective, non-blinded, single-center randomized controlled trial. The primary endpoint is the difference in total weight loss percentage (%TWL) 5&#xa0;years post-surgery. Secondary outcomes include excess weight loss percentage (%EWL), changes in obesity complications, quality of life, and adverse events related to the surgical procedures. The study population will consist of patients eligible for primary OAGB aged 18&#xa0;years and older.</p> Conclusions <p>The RiMini trial aims to investigate whether there is a significant difference in long-term weight reduction expressed as %TWL in patients undergoing an OAGB with or without the addition of a silicone ring 5&#xa0;years after surgery.</p> Trial Registration <p>This study is registered at Clinicaltrials.gov (NCT05472922) on the 25th of July, 2022.</p> Graphical Abstract <p></p>