Agenesis of the gallbladder without extrahepatic biliary atresia is a rare disorder. At the UCLA-affiliated hospitals, 12 patients were classified in the following groups: (1) multiple fetal anomaly, (2) asymptomatic, and (3) symptomatic. All four patients in the multiple fetal anomaly group died of their other congenital defects. In the three patients in the asymptomatic group, the absent gallbladder was an incidental finding at autopsy. The five patients in the symptomatic group underwent operations for symptoms suggestive of biliary tract disease, with no gallbladder found; all were symptom free postoperatively. Operative strategy should include a complete exploration, operative cholangiography, and common bile duct exploration as necessary. Possible mechanisms responsible for symptoms include primary duct stones, biliary dyskinesia, or nonbiliary disorders. Computed tomography, biliary manometry, upper gastrointestinal tract endoscopy, and endoscopic cholangiography (with or without sphincterotomy) could be employed if symptoms continue.