Micro RNAs (miRNAs) are small non-coding RNAs that regulate gene expression. Many studies show that they are implicated in essential physiological functions and particularly in tumors. Specific alterations of miRNA expression have been identified directly involved in carcinogenesis. Indeed, miRNAs could act as oncogenes or tumor suppressors. In addition, some miRNAs deregulations seem to be associated to specific tumors subtypes, suggesting that they could be used as tumor biomarkers. In this review, we summarize recent works about miRNAs and hepatocellular tumorigenesis in order to understand the role of these small non-coding RNAs in the carcino-genesis process and their possible use as diagnostic and prognostic markers of these tumors.