Adenosine to inosine （A-to-I） RNA editing is the most abundant editing event in animals. It converts adenosine to inosine in double-stranded RNA regions through the action of the adenosine deaminase acting on RNA （ADAR） proteins. Editing of pre-mRNA coding regions can alter the protein codon and increase functional diversity. However, most of the A-to-I editing sites occur in the non-coding regions of pre-mRNA or mRNA and non-coding RNAs. Untranslated regions （UTRs） and introns are located in pre-rnRNA non-coding regions, thus A-to-I editing can influence gene expression by nuclear retention, degrada- tion, alternative splicing, and translation regulation. Non-coding RNAs such as microRNA （miRNA）, small interfering RNA （siRNA） and long non-coding RNA （lncRNA） are related to pre-mRNA splicing, translation, and gene regulation. A-to-I edit- ing could therefore affect the stability, biogenesis, and target recognition of non-coding RNAs. Finally, it may influence the function of non-coding RNAs, resulting in regulation of gene expression. This review focuses on the function of ADAR-mediated RNA editing on mRNA non-coding regions （UTRs and introns） and non-coding RNAs （miRNA, siRNA, and IncRNA）.
