The Clinical Practice Guidelines for Hepatocellular Carcinoma (HCC), the first evidence-based guidelines for the treatment of HCC in Japan, were compiled by an expert panel supported by the Japanese Ministry of Health, Labour, and Welfare. This set of guidelines covers six research fields: prevention, diagnosis and surveillance, surgery, chemotherapy, transarterial chemoembolization, and percutaneous local ablation therapy. A systematic review of the English medical literature on HCC was performed, and a total of 7192 publications were extracted, mainly from MEDLINE (1966-2002). After the second selection, 334 articles were adopted for the guidelines to form 58 pairs of research questions and recommendations. For the users' convenience, practical algorithms for the surveillance and treatment of HCC were also created, which were based on evidence from the selected articles forthe guidelines and modified according to the current status of medical practice in Japan, where liver resection for HCC is regarded as safe with less than 1% mortality and cadaveric donors for liver transplantation are extremely difficult to obtain. The formation of the guidelines and the outline of their contents are described. The Japanese HCC guidelines may be useful in decision making at every clinical step, both for patients and physicians. Although the main users of these guidelines are assumed to be Japanese physicians, the accumulated evidence and interpretation in the guidelines may attract universal attention.