Agenesis of the gallbladder is a rare congenital anomaly occurring in 1 to 4 people of a population of 10000. It may present with biliary type symptoms such as upper abdominal pain requiring further investigation. Ultrasound is the first choice of imaging for biliary symptoms but is frequently misleading in the context of Gallbladder Agenesis. We report a case of congenital Gallbladder Agenesis and a biliary tract abnormality diagnosed by laparoscopy. As a result most patients are diagnosed following conversion of laparoscopic to open cholecystectomy and subsequent failure to identify the gallbladder. Failure to suspect Gallbladder Agenesis at laparoscopy can result in unnecessary open surgery and a high risk of bile duct damage with corresponding postoperative morbidity and mortality.