OBJECTIVE: Hepatocellular carcinoma (or HCC, Hepatoma) has been the first leading causes of death in Taiwan for recent years. HCC patients need similar treatment options (e.g., chemotherapy, radiotherapy, surgery°Ketc.), and generally require long-term medical care. This study, based on the evidences of National Health Insurance (NHI) database, evaluates the cost of illness (CoI) of HCC in Taiwan. METHOD: We analyzed the 2001 NHI data whose ICD-9-CM codes equal to 155.0, which stand for primary liver carcinoma. We calculated the CoI of HCC from two main cost sources: outpatient and inpatient. We calculated the outpatient CoI from four cost sources (including the cost of drugs, treatment, diagnosis and drug services), and the inpatient CoI from 17 cost sources (including the cost of surgery, beds, diagnosis, drugs, administrations°Ketc.). Also, we applied Cochran-Mantel-Haenszel (CMH) test to test the independence between gender and ages on HCC CoI. RESULTS: From the contingency table between gender and ages on HCC CoI, we may see the males who are 50-54 years old, males who are 35-39 years old and males who are over 65 years are the first 3 high HCC CoI groups. According the CMH statistics, the gender and ages are independent on HCC CoI (CMH p-value<0.0001) and the HCC CoI of males is significantly higher than females. The HCC CoI occupied the Taiwanese GNP about 1.41% in 2001. CONCLUSION: The three high HCC CoI groups could be a reference for further HCC clinical research about high HCC risk objectives. The HCC CoI evaluation can be a good index to show the state of the art of HCC treatment in Taiwan.