Abstract: Neuropeptides of the adipokinetic/red pigment-concentrating hormone family (AKH/RPCH) regulate energy metabolism in insects. The present study was carried out to elucidate the primary structure of an adipokinetic neuropeptide in the mango leaf webber, O. exvinacea employing bioassay, High Pressure Liquid Chromatography (HPLC) analysis and mass spectrometric studies. The presence of adipokinetic activity in the crude extracts of brain-retrocerebral complexes of O. exvinacea was demonstrated by heterologous in vivo bioassay in the polyphagous plant bug Iphita limbata. The extract was separated by Reverse Phase-High Pressure Liquid Chromatography (RP-HPLC) and the purified fractions were tested for their adipokinetic effects on the fat body. The maximum hyperlipemic activity was shown by fraction 10. MALDI-TOF-MS analysis of the fraction indicated that the molecular ion peak m/z value 1030.471 Da is indicative of sodiated adduct of peptide with mass 1008.471. This molecular ion peak has similar mass as that of already known AKH/RPCH peptide, Manduca adipokinetic hormone (Manduca AKH). Tandem MS/MS confirmed that the primary structure of O. exvinacea AKH is pE-L-T-F-T-S-S-W-G-NH2 which is identical with Manse-AKH.