Dieulafoy lesion is an often unrecognized cause of obscure, massive gastrointestinal haemorrhage. The lesion is usually located in the proximal stomach, but it may occur anywhere in the gastrointestinal tract. Dieulafoy lesions are routinely diagnosed and treated endoscopically. We describe a 65-year-old man who presented with severe lower gastrointestinal bleeding caused by a sigmoid colon Dieulafoy lesion and treated successfully with endoscopic haemoclipping.