Ruptured duodenal varix is a rare and easily neglected cause of upper gastrointestinal bleeding. A 52-year-old female patient manifested with frequent postprandial abdominal fullness and received endoscopic examination. Bleeding from this lesion was found during endoscopic manipulation. Injection sclerotherapy was tried but failed. Varix resection was performed. No rebleeding occurred during six months follow-up. Reviewing the literatures, the duodenal bulb is the most commonly involved site and liver cirrhosis is the major etiological factor, but the cause of this case may be extrahepatic portal obstruction. For any lesions in the gastrointestinal tract, endoscopic ultrasonography can be applied for the differential diagnosis if the diagnosis is doubtful. Endoscopic injection sclerotherapy and surgical intervention are the two main choices of treatment.