Polyglutamine(PolyQ) diseases comprise a group of inherited neurodegenerative disorders with significant clinical and genetic heterogeneity. Although they share a common mechanism involving dynamic expansion of CAG trinucleotide repeats, their clinical features may vary and there has been no specific treatment. Recently, much attention had been attracted to microRNAs which, as a new type of posttranscription regulatory factor, have proven to significantly affect the progress of PolyQ disease. This review will focus on the roles of microRNAs in the pathogenesis of PolyQ diseases and their potential use for therapy.