Ataxia with spastic diplegia was seen in seven males of a Turkish family, obviously transmitted as an X-linked recessive trait. The first clinical sign in infancy was nystagmus; ataxia and pyramidal signs were noted at age 2-3 years. Patients were never able to walk. Dysarthria, orthopedic impairment, and mild mental retardation appeared later as the disorder progressed. Death occurred in the 3rd or 4th decade from infectious diseases. The syndrome resembles X-linked spinocerebellar ataxia and X-linked spastic paraplegia in some aspects but is different if compared with previously published reports. Laboratory and neurophysiological studies showed no abnormalities. Various aspects of X-linked ataxia are discussed: genetic heterogeneity is apparent from observations reported.