Abstract: MicroRNAs (miRNAs) are endogenous, evolutionarily highly conserved noncoding single-stranded small RNAs. They play important roles in multiple biological and metabolic processes, including signal transduction, and cell proliferation, differentiation and apoptosis. MiRNAs can act as tumor suppressor genes or oncogenes, which are closely related to the formation of tumors. Recent studies have found that miRNA is closely related to thyroid cancer, and is involved in the occurrence and development of thyroid cancer, and is correlated with its highly invasive characteristics. In this paper the available data on miRNA deregulation in different thyroid tumors and the putative role of miRNA in thyroid cancer development were reviewed.