Although lung cancer is the commonest cause of death worldwide, metastases to the gallbladder are extremely rare. Two cases of gallbladder cancer attributed to metastatic lung cancer have been reported in the literature, but lung cancer with the initial presentation of acute cholecystitis due to metastases to the gallbladder has never been reported. Herein, we report a 78-year-old man who developed acute right upper quadrant abdominal pain as the initial presentation of the lung cancer due to metastasis to the gallbladder.