Miller Fisher syndrome (MFS), characterized as ataxia, areflexia and ophthalmoplegia, is generally considered as a variant of Guillain-Barré syndrome (GBS). However, some investigators believed that the syndrome could be explained by a central origin. To obtain more information about MFS for comparison with GBS, we conducted a retrospective study by analyzing the clinical data of MFS patients admitted to our hospital over a period of 11 years. The calibrated male/female ratio was 1.65. A seasonal clustering in winter was noted. The percentage of MFS among GBS was especially high (18%, 11/60) in Taiwan when compared with other series. Involvement of limb muscle strength, autonomic function and cranial nerves, except ocular motor nerves, was rarely found in our patients. When MFS is accompanied by limb weakness, it might represent a transitional form between MFS and GBS. Bulbar palsy and dysautonomia might predict a relatively poor prognosis. To obtain more reliable information, lumbar puncture should be done 1 week after disease onset, and electrophysiological tests should be done serially in every MFS patient. Eighty percent (80%, 4/5) of our patients were positive for IgG anti-GQ_1b antibody activity. In our study, there is more evidence indicating that MFS is a peripheral nervous system disorder; however, no definite conclusion could be made as to whether MFS is exclusively a peripheral or central nervous system disorder. We think MFS is an immune-mediated clinical entity which mainly involves the peripheral nervous system with rare involvement of other parts of the central nervous system.