The cancer registry is an essential part of any rational programme of cancer control. The information is the primary resource for epidemiological research and for planning and evaluating health services for the prevention, diagnosis and treatment of cancer. Epidemiological research, based on comprehensive cancer registration, remains the most valid and efficient way to plan and evaluate all aspects of cancer control. The estimated incidence of primary liver cancer in Thailand is very high, Liver cancer is the leading cancer in males and third in frequency in females. There is a very marked regional variation, with the highest incidence in the northeast, the age - standardized incidence rate of liver cancer in Khon Kaen is highest in the world. The percentage of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) varies greatly between regions. In Thailand, chronic infections with hepatitis B virus and the liver fluke, Opisthorchis viverrini are the major risk factors for the development of HCC and CCA, respectively. Primary prevention is an important approach for prevention and control of liver cancer.