Background: Prognosis in hepatocellular carcinoma (HCC) is influenced by both liver and tumor factors, which have been considered independent influences. However, recent evidence has shown that the underlying liver also has prognostic information. Aims: To investigate possible relationships between liver function parameters and HCC aggressiveness indices. Methods: A large HCC patient database with baseline clinical information and survival data was retrospectively examined. Results: Data on 756 HCC patients with normal bilirubin were examined for a relationship between serum liver enzymes and 4 HCC aggressiveness indices of maximum tumor diameter, portal vein invasion, tumor multifocality or serum alpha-fetoprotein levels. An association was found between elevated enzyme levels and increased HCC aggressiveness. An aggressiveness index was constructed from the 4 indices and expressed as a sum of their scores, which in turn reflected 3 survival groups. In a Cox model, the hazard ratios for each of the groups were significantly different. Conclusions: Statistically significant correlations were found between standard liver function parameters and HCC aggressiveness. A composite aggressiveness index was constructed, yielding 3 groups with different survival probabilities. These findings support the concept of the importance of the underlying liver in relation to HCC biology.