We present a case of obscure gastrointestinal bleeding associated with a large pseudoaneurysm in the splenic artery after simultaneous kidney-pancreas transplantation. Planar 99mTc red blood cell (RBC) scintigraphy demonstrated a focus of increased activity in the mid-abdomen, which was confirmed by SPECT/CT to be in the region of the pancreatic transplant. Subsequent diagnostic CT angiography of the abdomen identified a large pseudoaneurysm of the pancreas allograft splenic artery. At surgery, an arterial-enteric fistula was confirmed at the site of aneurysm coiling, and this segment of bowel was removed.