We have retrospectively investigated patients with hepatocellular carcinoma (HCC) (912 cases) treated in the Affiliated Hospitals of Keio University (the Keio Association for the Study of Liver Diseases: KASLD) and here we review the recent diagnosis and treatment of HCC. HCC is a major cause of death in Japan and a major etiology of this disease is chronic viral infection such as hepatitis C virus (HCV) and hepatitis B virus (HBV). Screening of HCC by imaging studies and measurement of serum tumor markers successfully prolonged survival of the patients in Japan. The prognosis of this disease has been determined by both tumor factors and degree of liver function, and its staging is usually established with a recent system such as Japan Integrated Staging Score (JIS). The 5-year survival rate of JIS stage 0, 1, 2 and 3 were 68.3%, 51.9%, 25.8% and 16.6%, respectively in our cohort. Multivariate analysis using Cox proportional hazard models showed that age (>65), HCV infection, tumor number, TB (>1.0), AFP (>20) and PIVKA-II (>40) were significant factors affecting survival among the entire patients. Major treatment strategies are hepatic resection, radio frequency ablation and transarterial chemo-embolization, but alternative treatments such as radiation, chemotherapy, and their combination have been used to reduce tumor sizes resulting prolongation of the survival or maintenance of patients' quality of life, while liver transplantation has not been popular in Japan. However, the overall survival continues to decrease from year to year, and does not show a plateau phase in Kaplan-Mayer curve. These results suggest that the best way to improve survival can be achieved by prevention of the disease. Antiviral therapies have decreased the incidence of HCC, indicating that treatment for chronic hepatitis is the best way to prevent HCC development at present.