The efficacy of controlled atmospheres of high nitrogen concentration (99.9%) and various carbon dioxide concentrations (25, 50,75and 99.9%) was investigated against adults and larvae of two insects attacking historic objects in Egypt, the black carpet beetle and the cigarette beetle. Also, the effect of temperature and exposures time on the mortality of insects was examined. Results revealed that the efficiency of CO₂ and N₂ gases was increased with increasing gas concentration, temperature and exposure time.  Carbon dioxide gas was more toxic to both insects than nitrogen gas at the same conditions.  Larvae of both species were more susceptible than adults to both gases.