The incidence of hepatocellular carcinoma (HCC) is increasing worldwide; the overall survival of patients with HCC is grim because most patients are diagnosed late, when curative treatment is not possible. Cirrhosis is the strongest risk factor for the development of HCC. HCC surveillance with alpha-fetoprotein (AFP) and ultrasonography has been recommended for persons with cirrhosis. However, AFP level is insensitive for the early detection of HCC, and ultrasonography is expensive and operator dependent. Clearly, there is a need for novel strategies for the early detection of HCC. The ideal biomarker assay for HCC would be sensitive, specific, noninvasive, reproducible, inexpensive, and acceptable to patients. The Early Detection Research Network of the National Cancer Institute has proposed 5 phases for biomarker validation: preclinical exploratory studies, clinical assay development for disease, retrospective longitudinal study to detect preclinical disease, prospective screening study, and cancer control studies. Several biomarkers, such as des-gamma carboxyprothrombin, lens culinaris agglutinin-reactive AFP, human hepatocyte growth factor, and insulin-like growth factor-1, are promising, but none of these markers has been validated for clinical use. Limitations of the current literature include inadequate sample size, heterogeneity in biomarker assay methods and result reporting, limited analysis of demographics and cause of liver disease as covariates in the expression of these markers, and a scarcity of longitudinal studies evaluating the ability of biomarkers to detect preclinical disease. There is an urgent need for novel biomarkers for the detection of early HCC; the National Cancer Institute proposal provides a framework for future validation studies.