Therapy with CpG ODN and MoAb enhances survival more effectively than therapy with control methylated ODN and MoAb. Immunocompetent C3H mice were inoculated with 2,500 tumor cells IP on day 0. Therapy consisted of MoAb alone, control methylated ODN alone, CpG ODN alone, control methylated ODN and MoAb, or CpG ODN and MoAb. Mice were followed for tumor development, toxicity, and survival. Each group contained 10 mice. Curves depict percent survival over 60 days. No mice living at day 60 developed tumor, and all survived more than 5 months. No toxicity was observed in any group. (▪) No therapy; (•) MoAb on day 3; (▴) control methylated ODN on day 2; (▵) CpG ODN on day 2; (⋄) control methylated ODN on day 2 and MoAb on day 3; (○) CpG ODN on day 2 and MoAb on day 3.