The Xanthogranuloma or granuloma of cholesterol is a degenerative lesion that occurs by a nodular accumulation of cholesterol and other lipids, accompanied by granulomatous inflammation. In reptiles, this is a poorly informed lesion, which has been associated with hyperlipidemia, dietary or hormonal factors and trauma. The aim of this report is to describe a xanthogranuloma in a 13-year-old female snake (Agkistrodon bilineatus), referred to the Department of Pathology of the Faculty of Veterinary Medicine and Zootechnics of the National Autonomous University of Mexico (FMVZ-UNAM), for postmortem analysis. The snake was presented with anorexia, depression, head tilt, chronic inflammation and hypercholesterolemia. Hepatic lipidosis and a cholesterol granuloma replacing 60% from the brain were diagnosed. The knowledge of this disease in snakes with neurological signs is important because they can be associated with the cause of death.