Miller-Fisher syndrome is a rare acquired nerve disease related to Guillain-Barré syndrome. Clinical features include asthenia, ocular muscle weakness with ophthalmoplegia, impaired limb coordination with instability, and absence of tendon reflexes. Swallowing disorders and rarely respiratory failure may be associated. The article aims to summarize, starting from the presentation of a clinical case, the latest updates which, in clinical practice, can be useful for a correct diagnosis and treatment of this condition which concerns both adult and pediatric patients.