The morphological characteristics of newly isolated Cordyceps hepialidicola were characterized, and the phylogenetic relationships with other Cordyceps species were investigated using a sequence analysis of the internal transcribed spacer (ITS). The PCR product of 592 bp showed a homology of 92 and 91% with C. militaris and C. nutans, respectively, In an in vitro model using mouse peripheral blood mononuclear cells (PBMC), a methanol extract of C. hepialidicola induced multiple cytokines, including IFN-${gamma}$ IL-4, and IL-18. The extract also enhanced the percentages of the CD4$^$+/ and CD8$sub$+/ T cells in the healthy murine PBMCs to 56.1% and 13.0%,respectively. The percentages of CD4$^$+/ and CD8$^$+/ in the untreated controls were 28.4 and 7.3%, and concanavalin A-treated positive controls were 62.4 and 18.3%, respectively.