A case-control study of risk for hepatocellular carcinoma (HCC) was carried out in our Department from December 1980 to December 1983. One hundred and twenty consecutive inpatients with HCC were compared with 360 controls pair-matched by sex and age (within years). For each case three different controls were selected from inpatients at the same hospital: one patient with liver cirrhosis; one patient with solid tumor and one patient with chronic illness other than neoplasm or liver disease. We report here the results on alcohol consumption, smoking habit and hepatitis B virus infection. The risk factors investigated are distributed similarly in HCC and cirrhosis. The prevalence of alcohol abuse in HCC is similar to that in cirrhosis and is significantly higher than in other neoplastic or otherwise chronically ill patients (odds ratio 2 X 3 and 3 X 2 respectively). Thus alcohol abuse is probably a risk factor for HCC as a cause of cirrhosis. Smoking habits were similar among the various disease groups and independent of alcohol consumption. The prevalence of heavy smoking was comparable in cases and controls. HbsAg negative-HCC with an ultrasonographic pattern of 'diffuse' alteration was more frequent in heavy smokers.