Over the last fifteen years, investigators have identified small non-coding RNAs as regulators of gene expression. One type of non-coding RNAs are termed microRNAs (miRNAs, miRs). MiRNAs which are evolutionary conserved, ~22nt single stranded RNAs that target genes by either inducing mRNA degradation or inhibition of translation. MiRNAs are implicated in many critical cellular processes including apoptosis, proliferation and differentiation. Furthermore, it is estimated that miRNAs may be responsible for regulating the expression of nearly one-third of the human genome. Despite the identification of over 500 mature miRNAs, very little is known about their biological functions and functional targets. In the last five years, researchers have increasingly focused on the functional relevance and role that miRNAs play in the pathogenesis of human disease. MiRNAs are known to be important in solid organ and haematological malignancies, heart disease, as potential modulators of the immune response and organ development. It is anticipated that miRNA analysis will emerge as an important complement to proteomic and genomic studies to further our understanding of disease pathogenesis. Despite the application of genomics and proteomics to the study of human lung disease, few studies have examined miRNA expression. This perspective is not meant to be an exhaustive review of miRNA biology, but will provide an overview of both miRNA biogenesis and our current understanding of the role of miRNAs in lung disease and a perspective on the importance of integrating this analysis as a tool for identifying and understanding the biological pathways in lung disease pathogenesis.