A high prevalence of serum IL-6 has been associated with the pathogenesis of hepatocellular carcinoma (HCC) in both animals and humans. However, it is not clear how the levels of serum IL-6 influence the prognosis of HCC patients. This study was carried out in order to attempt to answer this question.A total of 156 adults were selected and categorized into four groups: healthy subjects (n=18), those with tumor recurrence (n=26), those initially diagnosed with HCC (n=32), and those with HCC (n=80) who received curative resection between 2002 and 2004 with five years of follow-up. Serum IL-6 levels were determined in all subjects by the same ELISA method.IL-6 was found in high levels in the serum of patients initially diagnosed with HCC (8.47±5.92, p<0.0001) and in patients with HCC and tumor recurrence (12±31.90, p=0.001) compared with healthy subjects (0.89±1.51). This includes all patients who received therapy between 2007 and 2008. The levels of serum IL-6 were positively correlated with tumor size (p=0.002) in the HCC patients who received curative resection between 2002 and 2004 with five years of follow-up.High levels of serum IL-6 correlated positively with tumor size and with poor prognosis in HCC patients.