To study the effects of habitual alcohol intake on the latency period for the development of liver cirrhosis and hepatocellular carcinoma (HCC), 158 patients with cirrhosis and 79 with HCC were analyzed with respect to age at the time of diagnosis. They were classified into four groups based on hepatitis B surface antigen (HBsAg) in serum, and the history of intake of more than one small bottle of Japanese "sake" or an equivalent per day for more than 10 years. The average age of HBsAg positive male cirrhotics with a drinking habit (n = 10) was 38.8 years, 10.5 years younger than that of those without a drinking habit (n = 8) (P less than 0.05). The average age of HBsAg negative cirrhotics with a drinking habit (n = 97) was 47.9 years, eight years younger than that of those not drinking (n = 36) (P less than 0.001). There was no significant difference in the laboratory data between these groups. The average age of the HBsAg positive HCC patients with a drinking habit (n = 20) was 48.9 years, nine years younger than that of those without a drinking habit (n = 12) (P less than 0.05). The average age of HBsAg negative male HCC cases with habitual intake of more than 126 ml of ethanol per day was 51.0 years (n = 8), ten years younger than that of nondrinking male HCC cases (n = 11) (P less than 0.05). These data suggest that habitual alcohol intake may promote the development of liver cirrhosis and HCC, especially in HBsAg carriers.