Primary hepatoid adenocarcinoma of the gallbladder is rare. A 67-year-old woman presented with right upper quadrant abdominal pain with elevated α-fetoprotein level. Abdominal ultrasound and MRI showed a tumor in the gallbladder with normal liver. FDG PET/CT showed increased FDG uptake of the gallbladder tumor with retroperitoneal lymph node metastasis. Cholecystectomy was performed. Primary hepatoid adenocarcinoma of the gallbladder was confirmed by histopathology.