A u t h o r ' s p e r s o n a l c o p y Abstract Cowpea (Vigna unguiculata) is a subsistence crop for small and poor farmers from Latin America and Africa. This culture is com-monly damaged by cowpea weevil (Callosobruchus maculatus), which burrow into stored seeds to fed on. Due to impact of larval preda-tion, several plant defense studies have been developed, indicating that -amylase inhibitors are able to impede and/or reduce bruchids digestive process. In this report, a novel -amylase inhibitor from papaya seeds (Carica papaya) with activity against cowpea weevil enzymes was puriWed and biochemical characterized. Peeled seeds were macerated and extracted with a 0.6 M NaCl and 0.1% HCl solu-tion. Crude extract was precipitated with ammonium sulphate (100%). After dialyses, this rich fraction was applied onto a CM-Cellulose column and retained peak was submitted to an analytic reversed-phase column HPLC (Vydac C-18TP) yielding several peaks. Only one fraction, with molecular mass of 4562 Da, showed signiWcant inhibitory activity against C. maculatus -amylases. Otherwise, no inhibitory activities against mammalian -amylases were observed. Bioassays using artiWcial seeds containing C. papaya -amylase inhibitor rich fraction (0.5% and 1.0%) were also conduced showing that -amylase inhibitors were able to increase larval mortality (50%) and also decrease insect fecundity and adult longevity. These results showed the presence of an -amylase inhibitor from C. papaya seeds with high speciWcity to insect enzymes, indicating that this inhibitor probably could be used, through genetic engineering, in the construction of transgenic plants with enhanced resistance toward cowpea weevil.