Objective: To evaluate the effects of autologous tumor vaccines in preventing recurrences of hepatocellular carcinoma (HCC)., Methods: From March 1999 to June 2003, 80 patients with HCC undergoing resections were randomly assigned into a tumor vaccine group (n=40) and a control group (n=40). Tumor vaccines, consisting of formalin-fixed HCC tissue fragments, biodegradable sustained-releasers of granulocyte-macrophage-colony stimulating factor, interleukin-2, and an adjuvant, were developed. Every vaccine group patient received 3 vaccinations at a 2-week interval and the control group just received the adjuvant. Delayed-type-hypersensitivity (DTH) test and recurrent rates were analyzed., Results: Eight patients of the vaccine group and five patients of the control group were lost in the follow-up. Thirty-two patients completed the tumor vaccine procedure and no essential adverse effects occurred. 23/32 patients developed DTH responses against the fragments of HCC. The follow-up averaged 34.3 months (from 15 to 55 months). 1-, 2-, 3-year recurrence rates of the vaccine group were 12.6%, 35.9% and 54.0%, respectively; 1-, 2-, 3-year recurrence rates of the control group were 31.6%, 61.3% and 72.1%, respectively. The recurrent rate was significantly better in the tumor vaccine group than in the control group (P = 0.037)., Conclusions: Autologous tumor vaccine is a promising adjunctive modality to prevent recurrence of human HCC.