Objective: To determine the impact of cerebellar hemorrhage (CH) on mortality and adverse neurodevelopmental (ND) outcome rates in extremely preterm infants admitted to a tertiary neonatal unit. Study Design: A total of 1120 eligible infants (<28 weeks gestation) were born from 1998 to 2008 and had at least one cranial ultrasound. ND outcome was determined at 12 to 18 months corrected age.Results:Most CH (75%) occurred in infants <25 weeks gestation. CH did not affect mortality rates, however, it was associated with both mental and motor impairments, with incidence rate ratios of 3.08 (1.71 to 4.84) and 2.12 (1.12 to 3.45), respectively. Moreover, the risk of cerebral palsy (CP) was increased in infants with CH involving the medial part of the cerebellum. Conclusion: Our findings substantiate recent reports about the cerebellum, highlighting its role in cognitive and executive functions, and associating early cerebellar injury not only with CP but also with learning, affective and behavioral disorders. © 2012 Nature America, Inc. All rights reserved.