['C-reactive protein (CRP) is a practical prognostic marker in patients with hepatocellular carcinoma (HCC). We investigated the prognostic value of adding the CRP level to other validated staging systems (Cancer Liver Italian Program, Japan Integrated Staging, Barcelona Clinic Liver Cancer classification system, Tokyo score and tumor node metastasis classification) in HCC patients.', 'One hundred and eighty-six newly diagnosed HCC patients were retrospectively evaluated. A multivariate analysis identified the clinicopathological variables associated with overall survival; the variables identified were then added to each staging system and compared to those without the additional variable.', 'In multivariate analysis, an elevated serum CRP level was independently associated with a poor prognosis (hazard ratio 3.792, p < 0.0001). The addition of the CRP level to each of the established staging systems provided a higher linear χ(2) value and a lower -2 log likelihood than those without the addition of the term. Moreover, the area under the receiver-operating characteristic curve (AUC) analysis showed that the addition of CRP improved the AUC of each staging system.'] Does the addition of C-reactive protein to validated staging systems improve their prognostic ability in patients with hepatocellular carcinoma?