INTRODUCTION: There is a high incidence of gallstones in the Chilean population. PRESENTATION OF CASE: We report on a 57-year-old man who complained of abdominal pain in the right upper quadrant. Abdominal ultrasound indicated acute cholecystitis and a single, extremely large pear-shaped gallstone (16.8 cm long, and 7.8 cm at its widest point and 4.1 cm at its narrowest point). Its fresh weight (at operation) was 278.0 g and, after 4 years, its dry weight was 259.5 g. Emergency classical cholecystectomy was carried out successfully. DISCUSSION AND CONCLUSION: We have been unable to find a report of a larger gallstone in the English or Spanish language medical literature. © 2011 Published by Elsevier Ltd.