Hepatocellular carcinoma(HCC) is the leading primary liver cancer and its clinical outcome is still poor. MicroRNAs(mi RNAs) have demonstrated an interesting potential to regulate gene expression at post-transcriptional level. Current findings suggest that mi RNAs deregulation in cancer is caused by genetic and/or epigenetic, transcriptional and post-transcriptional modifications resulting in abnormal expression and hallmarks of malignant transformation: aberrant cell growth, cell death, differentiation, angiogenesis, invasion and metástasis. The important role of mi RNAs in the development and progression of HCC has increased the efforts to understand and develop mechanisms of control overt this single-stranded RNAs. Several studies have analyzed tumoral response to the regulation and control of deregulated mi RNAs with good results in vitro and in vivo, proving that targeting aberrant expression of mi RNAs is a powerful anticancer therapeutic. Identification of up and/or down regulated mi RNAs related to HCC has led to the discovery of new potential application for detection of their presence in the affected organism. Mi RNAs represent a relevant new target for diagnosis, prognosis and treatment in a wide variety of pathologic entities, including HCC. This manuscript intends to summarize current knowledge regarding mi RNAs and their role in HCC development. MicroRNAs (miRNAs) have demonstrated an interesting potential to regulate gene expression at post-transcriptional level. Current findings suggest that miRNAs deregulation in cancer is caused by genetic and / or epigenetic, transcriptional and post-transcriptional modifications resulting in abnormal expression and hallmarks of malignant transformation: aberrant cell growth, cell death, differentiation, angiogenesis, invasion and metástasis. The important role of mi RNAs in the development and progression of HCC has increased the efforts to understand and develop mechanisms of control overt this single-stranded RNAs. Several studies have analyzed tumoral response to the regulation and control of deregulated mi RNAs with good results in vitro and in vivo, proving that targeting aberrant expression of mi RNAs is a powerful anticancer therapeutic. Identification of up and / or down regula ted mi RNAs related to HCC has led to the discovery of new potential application for detection of their presence in the affected organism. Mi RNAs represent a relevant new target for diagnosis, prognosis and treatment in a wide variety of pathologic entities, including HCC. manuscript intends to summarize current knowledge regarding miRNAs and their role in HCC development.