A case-control study was undertaken to evaluate the roles of hepatitis B virus (HBV), blood transfusion, alcohol drinking and cigarette smoking in the etiology of hepatocellular carcinoma (HCC) in Osaka, Japan. A total of 229 cases and 266 hospital controls were included in our study. The relative risks of HCC obtained after adjustment for age, sex and other important variables were 14.3 (95% confidence interval (CI): 5.7–36.3) for HBsAg positives, 4.3 (95% CI: 1.9–9.6) for blood recipients and 3.2 (95% CI: 2.0–5.1) for heavy drinkers. A statistically significant dose-response relationship was observed between the risk of HCC and total alcohol consumption. The overall risk for HCC was also significantly elevated among smokers; however, there was no consistent dose-response relationship between the risk and cigarette consumption. We conclude that HBV, blood transfusion and excessive alcohol drinking play important roles in the etiology of HCC in Osaka, Japan. Further investigation is needed to clarify the possible etiological role of smoking.