**Abstract**

miRNAs are small noncoding RNAs, which are involved in epigenetic regulation of gene expression. Hepatocellular carcinoma (HCC), although not being at the top of most widespread cancers, nevertheless, remains among cancers with the most lethal cases. The chapter is dedicated to the epigenetic aspect of HCC development, namely the role of miRNA in this process. Being small and noncoding RNAs, they have a huge and significant function in gene regulation. This chapter will briefly cover following questions: miRNA biogenesis and function, metabolic and signaling pathways disrupted in HCC with a significant miRNA involvement, and main miRNAs contributing to HCC development and their targets.

**Keywords:** miRNA, hepatocellular carcinoma, target gene, gene expression, miRNA expression, diagnostic marker
