Hashimoto’s encephalopathy [HE] is an extremely rare condition associated with autoimmune thyroid diseases. It follows a nonspecific alteration of mental state which is characterized by abnormal consciousness, impaired attention and cognition, and associated changes in behaviour and personality. Although no particular pattern of cognitive dysfunction is specified, memory dysfunction is common. Diagnosis is made by excluding other toxic, metabolic, inflammatory, ischemic, and infectious causes of encephalopathy as well as primary degenerative CNS diseases, as was done with our patient.