Miller-Fisher syndrome, Guillain-Barre syndrome with ophthalmoplegia, Bickerstaff s brainstem encephalitis and acute ophthalmoplegia share some clinical features, and common anti-GQ1b IgG antibody and these are introduced as anti-GQ1b antibody syndrome. These syndromes mostly present with paralysis of extraocular muscles and internal ophthalmoplegia rarely occurs. We report a case of acute isolated bilateral internal ophthalmoplegia associated with anti-GQ1b IgG antibody.