The poison gland of the Diachasmimorpha longicaudata parasitic wasp contains an entomopoxvirus (DlEPV) that is injected into larvae of the host Anastrepha suspensa (Diptera: Tephritidae) during oviposition. Although DlEPV has been shown to inhibit encapsulation by host haemocytes, neither the identity of the associated gland components nor their functions are known. As a prelude to studies on the effects of poison gland proteins on host haemocytes, this study was initiated to determine the protein components of the poison gland using HPLC and tandem mass spectrometry (HPLC-MS/MS). Seventeen proteins were identified with 92% confidence, including homologs of 60, 70, and 90-kD heat shock proteins (HSP), as well as HSP cognate 3 CG4147-PA, isoform A of the honeybee, Apis mellifera. Several glycolytic enzymes and two Leonardo proteins (14-3-3) that presumably, are involved in signal transduction, were also identified. Interestingly, the parasitism-specific protein PSP24, previously reported from parasitized A. suspensa larvae, were also detected. The specific effects of these proteins on host cells are unknown; however, the homologies of some components suggest their likely function. For example, some heat shock proteins serve as chaperones, assisting in refolding proteins disrupted during stress while others prevent apoptosis. PSP24, a parasitism-specific protein found in both the wasp and the host, is induced by viral infection and is likely produced defensively. Further studies are necessary to ascertain their specific effects on host cells and their function within the poison gland itself.