To search for novel biologically active venom components, secretory venom proteins of two solitary hunting wasps, Orancistrocerus drewseni Saussure (1857) and Eumenes pomiformis Fabricus (1781), were identified by SDS-PAGE in conjunction with mass analysis with the aid of venom gland and sac-specific EST libraries constructed by suppression subtractive hybridization. Arginine kinase was the most predominant protein in both wasp venoms. Along with the full-length arginine kinase, a truncated form, which was known to have paralytic activity on a spider, was a common predominant protein in the two wasp venoms. Insulin/insulin-like peptide-binding protein was abundantly found only in E. pomiformis venom and the EST library, which might be due to its unique behaviors of oviposition and provision. It seemed that some venom proteins are secreted into venom fluid from venom gland cells via exosomes, not by signal sequence-mediated transport processes. Amphipathic α-helical peptides (10-15 amino acids) were predominantly transcribed in the venom gland/sac than protein components, and showed cell lytic activities against insect cells, mammalian cells, bacteria, and fungi. Phospholipase A2 and hyaluronidase, which are known to be the main components of wasp venoms, were found in both wasp venoms. In addition, a dendrotoxin-like peptide known to be a K+ channel blocker was also found in the venom of E. pomiformis.