Spinocerebellar ataxia type 1 (SCA1) is an adult-onset, dominantly inherited neurodegenerative disease caused by expansion of a glutamine repeat tract in ataxin-1 (ATXN1). Although the precise function of ATXN1 remains elusive, it seems to be involved in transcriptional repression. We find that mutant ATXN1 represses transcription of the neurotrophic and angiogenic factor vascular endothelial growth factor (VEGF). Genetic overexpression or pharmacologic infusion of recombinant VEGF mitigates SCA1 pathogenesis, suggesting a new therapeutic strategy for this disease.