MicroRNAs (miRNAs) are ~22 nucleotide non-coding RNA, which regulate expression of protein-coding genes through translation repression and/or degradation of mRNA. They are known to regulate cell proliferation and death and it has been found that miRNA expression signatures can distinguish cancer subtypes or predict biological and clinical behavior within the same cancer type. The understanding of miRNA function is likely to lead to novel therapeutically treatment of cancer. Combined computational/experimental approaches have played a significant role during recent years in the identification of novel microRNAs (miRNAs), as well as in the analysis of their function. We have developed several tools for analyzing the genomic organization and function of miRNAs ( DIANA-microT, TarBase, and miRGen) and a microRNA gene finder. Recently we have supported research on edited miRNAs in brain and investigated the role of SNPs within miRNA targets.