The prognosis of patients with hepatocellular carcinoma is related to the stage of the tumor at diagnosis and to the degree of liver function impairment induced either by the tumor itself or by the underlying cirrhosis. Any prognostic prediction should also take into account the potential impact of therapeutic interventions. Only surgical resection, liver transplantation and percutaneous ablation achieve a relatively high rate of complete responses in patients with tumors diagnosed at an early stage and may improve survival. By contrast, patients diagnosed at an advanced stage will receive palliative treatment with unproven survival benefits. Each stage and each treatment have their specific prognostic predictors. Thus, the most accurate prognostic system will have to use a specific model for each strata at which patients may be diagnosed: early, intermediate-advanced and terminal. Patients at an early stage may achieve a 5-year survival rate above 50%, those at intermediate-advanced present a 20-50% survival at 3 years and those at terminal stage die within six months. In addition to predicting prognosis, the staging system should also guide the selection of treatment and this is the major advantage of the classification applied in the Barcelona-Clinic Liver Cancer Group.