A 67-year-old man with a history of an attack of pancreatitis was repeatedly investigated for recurrent gastrointestinal bleeding necessitating blood transfusions. Routine investigations did not reveal the source of bleeding. Repeated angiograms also were not diagnostic. A hot spot identified on a 99mTc-pertechnate-labelled erythrocyte scan prompted an endoscopic retrograde cholangio-pancreatography (ERCP), which showed bleeding through the papilla of Vater. The source of bleeding appeared to be a small pancreatic pseudocyst. The patient was treated with a duodenopancreatectomy in which the pylorus was preserved. No rebleeding occurred since the operation. Pancreatic pseudocysts must be considered as a source of upper gastrointestinal bleeding in patients with bleeding of "obscure" origin. 99mTc-pertechnate-labelled erythrocyte scanning and ERCP may be helpful, even when angiography is normal.