The recent increase in the incidence of hepatocellular cancer in the United States is thought to underlie the rising mortality of this malignancy. However, it remains unknown whether survival of patients with hepatocellular carcinoma (HCC) has changed during the same time period. Using the SEER database (Surveillance, Epidemiology, and End Results) of the National Cancer Institute, we examined the temporal changes and determinants of survival among patients with histologically proven HCC over a 20-year period. Between 1977 and 1996, 7,389 patients diagnosed with HCC were followed in the survival database of SEER. The overall 1-year relative survival rate increased from 14% (95% confidence intervals (CI): 12-16) during 1977-1981 to 23% (95% CI: 21-24) during 1992 to 1996. Between the same two time periods, less improvement was seen in the 5-year survival rates, which increased from 2% (95% CI: 1-3) to only 5% (95% CI: 4-7). The median survival increased slightly from 0.57 years during 1977 to 1981 to 0.64 years during 1992 to 1996. In general, there were no significant differences in survival between men and women or between ethnic groups. During 1987 to 1991, a small fraction (0.8%) of patients underwent radical surgery; these patients had 1-year survival of 59% (95% CI: 35-83%), and 5-year survival of 35% (95% CI: 12-58%). Similar rates were seen during 1992-1996. In conclusion, a small improvement in survival of patients with HCC was seen between 1977 and 1996. Most of this apparent benefit is restricted to the first year following cancer diagnosis, raising the possibility of lead-time bias. There were no significant differences related to gender or ethnicity.