Abstract: Objective:To investigate the antitumor effect of 5-fluorocytosine/cytosine deaminase (5FC/CD) suicide gene system combined with heat shock protein-peptide complexes(HSP-PC) tumor vaccine. Methods:Adenoviruses containing E.coli CD gene were injected into murine tumor followed by intraperitoneal murine 5-FC. Meanwhile, mice bearing tumor were inoculated s.c with HSP-PC.Results:In mice bearing tumor, the combined therapy led to reduction in tumor growth and complete tumor regression was observed in 70% mice. After the combined therapy, the tumor mass showed obvious necrosis and inflammatory cell infiltrcition, more CD 4 + and CD 8 +T cells infiltrated into the tumor tissue, and the murine CTL activities increased significantly. Conclusion:The combination therapy with 5-FC/CD system and HSP-PC tumor vaccine is very effective for murine melanoma, and has potential clinical useages.