The authors reviewed clinical profiles and laboratory findings for 100 cases of abducens nerve paresis without impairment of the other cranial nerves, limb weakness, and ataxia throughout the clinical course. Review of the medical records of 9300 patients referred to our neuoroimmunological laboratory for serum anti-ganglioside antibody testing. Information was obtained from each primary physician on symptoms of preceding infection; initial symptoms; neurological signs during the illness; the clinical course; treatment provided; and outcome. Isolated abducens nerve paresis was present in 100 patients and bilateral paresis in 29. Tentative diagnoses made by the primary physicians on request of anti-ganglioside antibody testing were abducens nerve palsy (n = 68), Fisher syndrome (n = 14), acute ophthalmoparesis without ataxia (n = 14). Symptoms of infection anteceded in 63. Tendon reflexes were absent or decreased in 27. Distal paresthesias were experienced by seven. Serum anti-GQ1b antibody was positive in 25. These findings suggest that some cases of isolated abducens nerve palsy can be categorized as a regional variant of Guillain-Barré syndrome or mild form of Fisher syndrome.