Abstract In the United States, the most common surgical procedure for morbid obesity is the Roux-en- Y gastric bypass. Pulmonary embolism, leak, bowel obstruction, and gastrointestinal bleeding are among the potential early fatal complications. Early postoperative bleeding after laparoscopic gastric bypass, although uncommon, presents a dilemma because of the danger of perforation from postoperative endoscopy and the inability to access the gastric remnant easily. We describe a case of a Mallory-Weiss tear causing massive upper gastrointestinal hemorrhage 1 week after laparoscopic Roux-en- Y gastric bypass. Bariatric surgeons should consider this diagnosis, especially when encountering a patient with a history of significant retching postoperatively.