Aging is characterized by a progressive decline in the efficiency of physiological function and by the increased susceptibility to disease. Recently, the prevalence of elderly hepatocel- lular carcinoma (HCC) has been increasing in Japan. Inflammation, DNA-damaging agents (reactive oxygen and nitrogen species), methylation/ demethylation of DNA, and shortening of the telomere will lead. to genetic changes in pro- liferating cells and hepatocarcinogenesis. Because, these factors and processes are interlinked, it is difficult to assert the main causes of hepatocarcinogenesis. In conclusion, aging has become one of the most important risk factors for HCC. The inves- tigation of the mechanism of hepatocarcinogenesis by aging would have potentially impor- tance that lead to the novel diagnostic system, treatment strategy and prevention for HCC in the elderly.