A 43 year old woman presented with attacks of abdominal pain, haematemesis and hyperamylasaemia. Gastrointestinal X-rays and repeated upper gastrointestinal endoscopy failed to reveal the source of bleeding. Ultrasound and computed tomographic scan demonstrated a calcified mass in the tail of the pancreas. Surgical exploration revealed a solitary mass in the pancreas and histological examination showed cystadenocarcinoma. The patient died 2 years later because of local recurrence, but haematemesis and melaena did not recur. This case presents an unusual manifestation of cystadenocarcinoma of the pancreas with massive bleeding from the tumour via the pancreatic duct and associated pancreatitis. Other possible reasons for bleeding with cystadenocarcinoma of the pancreas are discussed.