The majority of cases of hemobilia are of traumatic or vascular origin; however, we report herein the rare case of a 51-year-old man with early carcinoma of the gallbladder accompanied by hemobilia. He had been diagnosed as having gallbladder polyps during an admission to a local hospital for treatment of cardiac failure. Preoperative evaluation in our hospital suggested that the polypoid lesion was an advanced carcinoma of the gallbladder. Laparotomy revealed that the gallbladder contained blood clots, and a cholecystectomy was performed. Histological examination confirmed the main lesion to be IIb-type early carcinoma of the gallbladder and proved that the blood clots had been misinterpreted as polyps or advanced carcinoma before the operation. The diagnostic approaches and characteristics of hemobilia in the gallbladder are discussed with a review of the literature.