Hepatocellular carcinoma (HCC) is the fifth most common malignant cancer and the third leading cause of cancer death worldwide. Molecular profiling of changes in gene expression has improved our understanding of the HCC mechanism, allowing the identification of biomarkers for HCC diagnosis and HCC patient stratification for prognosis and therapy. Recently, a new group of molecules, microRNAs, has been discovered to be aberrantly expressed in HCC and some of them are functionally involved in HCC carcinogenesis and progression. Further, certain microRNAs are associated with HCC or related to HCC subtypes, implying the potential of microRNAs for HCC patient stratification of diagnosis and prognosis. Some of these HCC-associated microRNAs have been validated in independent cohorts, paving the way for developing clinically useful platforms to assess HCC risk, aiding HCC diagnosis and assisting in HCC patient stratification with the potential for personalized adjuvant therapy. Here, we mainly focus on the diagnostic and prognostic roles of miRNAs as a group of new biomarkers for HCC.