X-linked congenital nystagmus is a rare disorder in which affected males manifest binocular uniplanar nystagmus with associated head oscillation. In the families previously reported, affected females have been described. We report on a multigeneration family with X-linked congenital nystagmus with an affected woman. She was a (46,XX/45,X) mosaic. Magnetic resonance images of the brain of affected individuals were normal.