The multiple myeloma SET domain (MMSET) involved in the t(4;14)(p16;q32) chromosomal translocation encodes a histone lysine methyltransferase. High expression of MMSET is common translocation in multiple myeloma (MM) and is associated with the worst prognosis. Recent studies have shown that overexpression of MMSET is significant in other tumor types compared to their normal tissues. However, little is known about its role in hepatocellular carcinoma (HCC). In these study we investigate the expression of MMSET in HCC and to make correlations with clinicopathologic features. Twenty-eight pairs of HCC and adjacent non-tumor tissues, and eight normal liver tissues were collected for MMSET detection by western blotting and real time-PCR analysis. Immunohistochemistry was used to determine the expression of MMSET in HCC and adjacent non-tumor tissues from 103 patients. Overexpression of MMSET was significantly associated with Edmondson stage, vascular invasion. Moreover, Kaplan-Meier curves showed that MMSET upregulated was associated with shorter overall survival and disease-free survival in HCC patient. In conclusion, our study demonstrates for the first time that overexpression of MMSET is an independent prognostic factor and is correlated with poor survival in HCC patients.