Fumigation experiments were carried out ir the laboratory at 26+1C and 60+5% RH to study the effectiveness of three cartx1 dioxide concentrations (23, 46 and 68%) in controlled atmospheres on tw insect species attacking stored products, namely C. chinensis (L.) and S. grnarius (L) A marked differences in susceptibility of the two species to the cangeinthe atmospheric constitutes were recorded, whereas the adults, larvae PuPae» ^d eggs of C. chinensis were more susceptible to carbon dioxide than tose °^^ granarius. Time required to obtain certain mortality for tf vari°us stages of both species were generally decreased with increasing CO concentrations. Also results showed that pupae and eggs of S. gr. were te most tolerant stages followed by adults and larvae. ~ ;= st ;, In case of T. chinensis adults were the most stage to carbon dioxide