Severe injury to the cerebellum as a complication of extreme prematurity with extremely low birthweight was recently described in 13 children with the clinical diagnosis of cerebral palsy. We report another 10 cases of this syndrome. The clinical features include striking motor impairment and variable degrees of ataxia and athetosis or dystonia, which represent a distinct clinical type of cerebral palsy. Most are severely damaged, with cognitive, language, and motor delays. All are microcephalic, except one with hydrocephalus. Neuroimaging studies demonstrate the absence of major portions of the cerebellum involving both the inferior vermis and hemispheres. Most also have injury of a less severe nature in the cerebrum. This report indicates that this is not an uncommon outcome of extremely low birthweight infants, and we hope to encourage further investigations into the relative frequency and likely etiologies of the condition. (J Child Neurol 2004;19:139—142).