Since Miller Fisher's first report in 1956, evidence has accumulated about clinical and laboratory features, immunopathogenesis and treatment of Fisher syndrome (FS). Our literature review revealed the nature of FS. It has relatively uniform clinical and laboratory features. Ophthalmoplegia, ataxia and areflexia are essential prerequisites for an FS diagnosis, but there are several clinical variants with isolated ophthalmoplegia or ataxia. The discovery of serum anti-GQ1b antibody in FS has led to breakthroughs in FS research. The antibody is thought to be a key factor in the pathogenesis of FS, the understanding of which has progressed owing to the discovery of molecular mimicry between GQ1b and the lipo-oligosaccharides of Campylobacter jejuni and Haemophilus influenzae. The lesions responsible for the clinical symptoms have been debated but are close to clarification. Hence, the pathogenesis of FS has been made much clearer, although there are still some unanswered questions.