MicroRNAs (miRNAs) comprise a family of small, endogenous, noncoding functional RNA molecules that have emerged as key post-transcriptional regulators of gene expression. They inhibit the translation of proteins from mRNA or promote its degradation. Aberrant miRNA expression has been linked to various human diseases and measurement can differentiate between normal and diseased tissue. Expression is tissue-specific and any changes in miRNA expression within a tissue type can be correlated with disease status. Altered miRNA expression has been reported in the smoking-related diseases cancer, chronic obstructive pulmonary disease and cardiovascular disease. Additionally, miRNAs are thought to have vital roles in inflammatory cell differentiation and regulation. miRNAs might, therefore, be useful biomarkers for early detection of disease-related molecular and genetic changes. In this review, we summarize the available scientific evidence for the potential of miRNAs as biomarkers of smoking-related diseases. Studies should be carried out to identify the miRNAs most relevant to specific diseases.