We developed a tumor vaccine consisting of fixed hepatocellular carcinoma (HCC) cells/tissue fragments, biodegradable microparticles encapsulating granulocyte‐macrophage‐colony stimulating factor and interleukin‐2, and an adjuvant. The vaccine protected 33% of syngeneic mice from HCC cell challenge. The vaccine containing human autologous HCC fragments showed essentially no adverse effect in a phase I/IIa clinical trial and 8/12 patients developed a delayed‐type hyper‐sensitivity (DTH) response against the fragments. Although 2 of 4 DTH‐response‐negative patients had recurrence after curative resection, the DTH‐response‐positive patients had no recurrence. The time before the first recurrence in the vaccinated patients was significantly longer than that in 24 historical control patients operated in the same department (P<0.05). This formulation is a promising candidate to prevent recurrence of human HCC.