Azadirachtin was isolated from 4 kg. of neem seed kernels by solvent extraction and purified by column chromatography and reversed-phase high-performance liquid chromatography, respectively. The yield of 11.9 mg. with 92.87% purity was obtained. Fraction F003 from methanol extract, F004 from ethyl acetate extract, F007, F011, F016, F022, F027 from column chromatography and F030 from reversed phase HPLC containing azadirachtin were tested for a acute toxicity and antifeedant activity against the greater wax moth (Galleria mellonella L.) by a feeding bioassay. The test was carried out by feeding each fractions mixed in the feed at the concentrations of 0.01, 0.05, 0.1, 0.5 and 1.0 mg./mg.feed. The LC50 values were determined within 72 hours. Fraction F030 had LC50 value was 0.0412 mg./mg.feed indicating having high biological activity. Furthermore, F003, F004, P007, Foil, F016, F022, F027 showed moderate antifeedant activity, while fraction F030 had highest activity.