The present work aimed to study the efficacy of some inert dusts, i.e., calcium carbonate (Caco₃), white cement, black cement, sand, espidage, phosphate rock, sulfur flowers, talc powder (Mgo), animal dung ash, zinc dust, diatomaceous earth (DE), silica gel and katel-sous (Ks) against adults of the rice weevil, Sitophilus oryzae (L.) on two grain hosts (wheat and rice) comparing with the organophosphorous insecticide malathion. The results indicated that adult mortality was concentration and exposure period dependent. The most effective dust was katel-sous (Ks) powder. The next effective dust was black cement, the other tested materials recorded different percentages of cumulative mortality and could be arranged descendingly according to their efficiency as follows: sulfur flowers dust, diatomaceous earth, white cement, phosphate rock, zinc dust, animal dung ash, espidage, calcium carbonate, talc dust, sand and silica gel dust. The order of efficiency of these dusts was changed when tested on rice grain. The number of progenies descended from adults of S. oryzae that survived with the tested dusts for a period of 15 days on wheat and rice grains were influenced significantly by the type of dusts. The lowest number of progeny was produced by the survivors of sulfur dust. The highest number of progenies was recorded for the insects of control. The tested materials affected significantly the grain weight loss. Sulfur dust was the most effective protectants as it reduced the grain weight loss to the lowest value. The least effective dust in reducing grain weight loss was silica gel dust. On rice grains the percentages of grain weight loss were generally less than those of wheat grains because the rice grains were less preferable for breeding this insect, so, the numbers of produced progenies were less than those on wheat. All tested dusts attained some protection to treated grains, therefore, germination of grains treated with these dusts was generally increased.