Hashimoto encephalopathy is a rarely diagnosed autoimmune neurological disorder, associated with the presence of antithyroid antibodies. The variability of clinical presentation, rarity of the disease, and absence of specific diagnostic markers make timely diagnosis very complicated. This article describes a clinical case of a female patient with Hashimoto encephalopathy and discusses diagnosis, differential diagnosis and treatment approaches. We emphasize the importance of establishing a timely diagnosis, considering high efficacy of targeted treatment.