Tests were carried out to study the toxicity, oviposition suppression, ovicidal and larvicidal effectsof Chenopodium ambrosioides L. as powder, extracts and essential oil against Callosobruchus maculatus F. (Coleoptera: Bruchidae),Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) and Tribolium castaneum Jacqueline du Val. (Coleoptera: Tenebrionidae). The powder formulation was more toxic to S. zeamais than either C. maculatus orT. castaneum with 48 h LC50 values of 0.46 g/kg, 1.60 g/kg and 2.14 g/kg, respectively. Ethanol extract was more toxic to C. maculatus with a 48 h LC50 value of 0.023 g/l, than other test insect species. The essential oil treatment demonstrated higher fumigant toxicity against C.maculatus than S. zeamais with 24 h LC50 values of 1.33µl/l and 1.90 µl/l respectively. The oil vapour showed activity against C.maculatus egg, but had no appreciable larval mortality. The weight loss of grains admixed with C. ambrosioides powder was lower than the controls after 150 days of field storage.