Life-threatening hemobilia is a rare cause of gastrointestinal hemorrhage. Giant choledochal cyst is also a rarely reported diagnosis. Similarly, arteriocholedochal fistulas are also rarely reported and usually occur after invasive procedures for diagnosis or treatment of hepatopancreatobiliary-related disorders. In this report, the authors describe a case of a spontaneous arteriocholedochal fistula that occurred in a giant choledochal cyst and led to life-threatening hemobilia. The patient ultimately required a Whipple’s pancreatoduodenectomy for treatment, which is again rarely undertaken as an emergency procedure. We describe the management this patient underwent and discuss the reasons why we resorted to undertake such a formidable procedure for the patient as his treatment option.