The contact toxicity of indoxacarb, abamectin, endosulfan, insecticide soap, S-kinoprene and dimethoate to Orius insidiosus (Say) and Aphidius colemani Viereck were studied in the laboratory. These beneficials are often used in the greenhouses to manage various insect pests. Indoxacarb is slow acting and therefore, to estimate lethal dosages, observations should be continued for several days until data stabilize. Seven days after treatment, the LC50 was 0.119 gAI litre-1 for O insidiosus adults and 0.019 g AI litre-1 for A colemani. At that time, the recommended field concentration was 0.479 times the LC50 for O insidiosus adults and three times the LC50 for A colemani. In contrast, indoxacarb had no adverse effect on the reproductive capacity of wasps surviving a treatment or the developing wasps in the aphid mummy. Among the other insecticides S-kinoprene was the most innocuous while dimethoate was the most toxic to the two beneficials. The other insecticides had overlapping toxicities. [copyright] 2004 Society of Chemical Industry. Aphidius colemani (Aphidiidae) Orius insidiosus (Anthocoridae) Ecology; Population dynamics; Abiotic factors; Chemical factors Aphidius colemani; Orius insidiosus; Mortality; Fertilizers and pesticides; Insecticides toxicity to non-target organisms none