MicroRNAs are small RNA molecules and constitute a relatively novel class of gene expression regulators, found in the great majority of eukaryotic cells. Their role in human physiology and pathology is actively being researched with new exciting discoveries continuously coming to the forefront. MicroRNAs play a crucial role in the biogenesis and function of the cardiovascular system and act as important regulators of various metabolic and signaling pathways in cardiovascular disease. In this review there will be a summary on current knowledge about the expression, regulation and function of microRNAs in the most common diseases of the cardiovascular system as well as a presentation of and discussion about their promising future role as new biomarkers and therapeutic targets.