This study investigated the relationship of telomerase activity to its clinical implications in hepatocellular carcinoma (HCC). Telomerase activity was quantatively examined by a non-radioisotope quantitative system based on a TRAP-eze (ONCOR) in 42 HCC nodules and 40 non-cancerous liver tissue adjacent to the HCC nodules, obtained by surgical resection. Telomerase activity was confirmed in 37 HCC nodules (88.1%), being more statistically intense in de-differentiated tumors (p<0.01). Telomerase activity was positive in 9 cases (22.5%) of non-cancerous liver tissue and its activation was closely associated with the biologically malignant potential of the tumor itself such as the histological grade, portal vascular invasion, and intrahepatic metastasis (p<0. 05). The disease-free survival rate with its activity was also statistically lower than that without its activity of the non-cancerous tissue (p<0.01). These results indicate that telomerase may be a useful marker of biological characteristics in HCC and may lead to more effective surgical procedures.