With the epidemic prevalence of obesity in today's society, bariatric surgery has become very popular in treating severe obesity. Although the complications of this surgery have decreased with the advancement of medicine and post-treatment care, there are still complications that can lead to death if neglected. In this case report, we present a 44-year-old patient who underwent redo bariatric surgery. She was discharged from the hospital in good general condition but returned a few days later with a major complaint of abdominal pain and sudden bleeding from the upper gastrointestinal tract. After performing CT and endoscopy and considering the results, the patient underwent laparotomy, which showed a fistula between the splenic artery and the remnant of the stomach. After surgery and after the recovery period, the patient was discharged from the hospital. In this case report, we describe for the first time an uncommon and unique complication following redo bariatric surgery. We suggest that a fistula between the splenic artery and the remnant of the stomach should be considered in patients with abdominal pain and upper gastrointestinal bleeding who underwent redo bariatric surgery.