Two stacks of Western White Wheat (Grade II), each weighing 157 tonnes, measuring 30'x20'x14', and containing common stored grain insect pests were fumigated under rubberized gas-proof covers with Ethylene dichloride and Carbon tetrachloride (3:1) (EDT/CT mixture) and Hydrogen Phosphide (Phostoxin) at 20 lbs./1,000 cu.ft. and 2 tablets per tonne respectively. The temperature and relative humidty were 84°F. and 76per thousand respectively and the moisture content of the grain was 11.5per thousand ± 0.5per thousand. Two other stacks, each containing 33 tonnes of U.S. Western White Wheat (Grade II), heavily infested by R. dominica (F.) and measuring 14'x9'x11', were also fumigated with ED/CT mixture and Phostoxin under gas-proof covers employing similar dosage rates. The exposure period allowed was 48 hours in the stacks fumigated with ED/CT mixture and 7 days for the lots fumigated with Phostoxin. Under the experimental conditions, Phostoxin proved to be more effective than ED/CT mixture to control the infestation of Rhizopertha dominica (F.), Tribolium castaneum (Hbst.), Oryzaephilus surinamensis (Waterh.), Latheticus oryzae (L.) (Waterh.) and Larvae of Cadra (Ephestia) Cautella (Walk). Phostoxin was observed to exert considerable control also on the latent (hidden) infestation by R. dominica (F.) and larvae of C. cautella (Walk.). Pre-adult stages of S. oryzae (L.) were, however, found to be slighly resistant.