Enteric drainage of secretions by anastomosing the donor duodenum to the recipient's small bowel has become common in pancreatic transplantation. While it eliminates many problems, endoscopic access to the transplanted duodenum and pancreas is made difficult. After a pancreas kidney transplant, the patient presented with massive hematochezia. Upper and lower endoscopy revealed large amounts of red blood in the colon but no specific bleeding site. Mesenteric angiography was normal but pelvic angiography showed rapid extravasation of contrast from a pseudoaneurysm of the pancreatic transplant artery. This was successfully embolized with coils. To the best of our knowledge, this is the first case of massive gastrointestinal hemorrhage because of rupture of a pseudoaneurysm of the donor pancreatic artery in a pancreas transplant patient. We report this case and review our institution's experience with all forms of gastrointestinal bleeding in pancreas transplant patients.