Adults and larve of Trogoderma glabrum (Herbst) and rice weevil, Sitophilus oryzae (L.), and pupae of Indian-meal moth, Plodia interpunctella (Hubner), were exposed 3, 7, or 14 days to conditioned binary and ternary mixtures of N2, O2, and CO2 at 4.4°, 15.6°, 26. 7°, and 37.8°C. Atmospheres were highly lethal to the moth pupae and, except at the lowest temperature, to the beetle adults when the O2 concentration was reduced to about 13per thousand and the CO2 concentration increased to at least 43per thousand. However, for the atmospheres to be highly lethal to T. glabrum larvae, the O2 had to be reduced to about 7per thousand and the CO2 increased to 60per thousand or more. In the absence of CO2, atmospheres were not lethal to the insects until the O2 concentrations was reduced to about 1per thousand.