Efficacy of ozone gas against two of stored product insects, larvae and eggs of almond moth Ephestia cautella (Walker) (Lepidoptera: Pyralidae)and larvae and adults of the saw-toothed grain beetle, Oryzaephilus surinamensis (Coleoptera: Cucujidae) at 30 ± 1°C was tested. The results showed that mortality increased gradually by increasing exposure time of ozone gas. Mortality percent for larvae of E. cautella was 10% at 0.5 h. exposure and reach to 100% at 4 hrs. after 7day of exposure period.  Reduction of egg numbers was 7.65% at 0.5 hrs. exposure period and increased to 81.25% at 4 hrs. These results showed that eggs more tolerant to ozone gas than the larvae. Mortality percent of O. surinamensis adults was 5.2% at 1h. exposure period and increased to 90.4% at 4 hrs. after 7 days of exposure. Mortality of larvae of O. surinamensis was 6.4% at 0.5 hrs. exposure and increased to 92% at 4 hrs. after 7 days of exposure period.