Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Early diagnosis improves the prognosis. Protein induced by vitamin K antagonist-II (PIVKA-II) is an effective serum biomarker for HCC diagnosis and prognosis. Combined with another serum biomarker alpha-fetoprotein (AFP), the sensitivity and specificity of HCC diagnosis can be improved to a maximum of 94 and 98.5 %, respectively. PIVKA-II alone or in combination with AFP and/or AFP-L3 was effective in predicting the treatment response and clinical outcome of curative hepatic resection, chemotherapy, targeted therapy, radiotherapy, and liver transplantation. Japanese clinical guidelines recommend the combined use of PIVKA-II and AFP for the diagnosis of HCC, management of high-risk population, and prognosis of anticancer treatment. Further, PIVKA-II as a functional target promoted HCC cell proliferation, invasion, and metastasis by activating c-Met and other signal transduction pathways. Inhibition of PIVKA-II may provide a selective and effective therapy for HCC.