Abstract: MicroRNAs (miRNAs) are a major class of endogenous small RNA molecules that post-transcriptionally regulate gene expression.Several miRNAs have been proved to be related to human cancers,including lung cancer.The loss of several tumor suppressor miRNAs and the overexpression of certain oncogenic miRNAs have been observed in lung cancer.In this review,we summarize our current understanding of the role of miRNAs in the development of lung cancer and their potential role as novel drug targets.Furthermore,we also describe the relationship of miRNA with the diagnosis,therapy,and prognosis of lung cancer.