microRNA (miRNA) are about 22 nucleotide (nt) endogenous small non-coding RNA that play an important role in regulation of gene expression at the post-transcriptional level. miRNA control the expression of genes involved in several biologic processes, including apoptosis, proliferation, differentiation and metabolism of cells. miRNA can also act as oncogenes or antioncogenes. Abnormal expression of miRNA is associated with chronic myelogenous leukemia (CML) and contributes to the pathogenesis, disease progression, and response to therapy of CML. They may also serve as the potential therapy targets in the disease. In this review, the most important findings about the biogenesis pathway and function of miRNA as well as the role of miRNA in the pathogenesis, drug-resistance and therapy of CML are discussed.