Simultaneous kidney-pancreas transplantation (SKPTx) with enteric drainage is an acceptable treatment for selected patients with type 1 diabetes mellitus and end-stage renal failure but it may be associated by complications such as gastrointestinal bleeding (GIB). Case report: 3 patients presented with severe anemia 3-6 months after SKPTx with enteric drainage. We had used a Roux-en-Y loop with end to end anastomosis to donor duodenal c-loop for enteric drainage in all 3 cases. Pancreas and renal function were normal. Stool occult blood testing was 4+ positive and lab data was consistent with severe iron-deficiency anemia. Assay for cytomegalovirus (CMV) antigenemia was negative. Upper and lower GI endoscopy were nondiagnostic. In the first case (23 y/o male) radiolabelled red blood cell (RBC) scan showed a source of bleeding in the center of abdomen. Because of recurrent need for transfusion the patient underwent laparotomy and intraoperative endoscopy through a small incision in the jejunoileal junction showed that the source of bloody stool was from proximal site of Roux-en-Y. A longitudinal incision in the c-loop showed multiple bleeding ulcers. Second and third patients were 26 and 27 y/o females with the same presentation who underwent operation w/o RBC scan and intraoperative finding were the same. In all 3 patients large ulcers were oversewed and the anastomosis revised to a side-to-side fashion for better drainage of donor pancreas. During the 18-24 months of follow-up the patients had no recurrence of anemia w/o any need to transfusion or iron supplements. In conclusion, high donor pancreas exocrine output associated with relatively low drainage of a small end-to-end anastomosis may be the cause of occult GIB after SKPTx. It is recommended to use a side-to side anastomosis to prevent this complication.