Adenoma of the gallbladder is an uncommon benign tumor among pediatric patients. Rarely, it can cause of hemobilia. A 7-year-old boy was referred to our clinic due to active bleeding of the ampulla vateri, which was detected by upper gastrointestinal endoscopy. Initial hemodynamic parameters were stable. Conjunctival icterus and melena were observed on performing the physical examination. Computed tomography revealed dilatation of the common bile duct. The bleeding point was not detected on scintigraphy and angiography. During diagnosis, the hemoglobin level decreased and hemodynamic instability occurred; exploratory laparotomy was planned due to suspicion of hemobilia. A mass of gallbladder was detected, and cholecystectomy was performed. An intraoperative evaluation of the gallbladder revealed two irregular polypoid masses with coagulum; they were approximately 1 and 2 cm in diameter and on the fundus. The patient was discharged on the postoperative 13th day uneventfully. A tubulopapillary adenoma of the gallbladder was diagnosed after the patients underwent a histopathological examination. Hemobilia is a term used to describe blood in the biliary tract, and it is a rare cause of gastrointestinal bleeding. The clinical presentation of gallbladder polyps with hemodynamic instability due to tumoral hemorrhage is a challenging course for physicians. Further, preoperative determination of the source of bleeding is not always possible. Hemobilia due to gallbladder polyps must be kept in mind when gastrointestinal bleeding is present among pediatric patients.