<p>The quality of grains is influenced by storage pests, which are not only spoilers of stored grain, but also vectors of human and animal diseases. Chemical pesticides play an essential role in the cultivation and storage of cereals. However, due to the low degradability and residual toxicity of synthetic pesticides on the environment and non-target organisms, as well as the increasing resistance of target organisms to them, consideration should be given to the development of alternative pest control agents. Modified or controlled atmospheres (MAs or CAs) with higher or lower concentrations of atmospheric gases, mainly oxygen (O2), carbon dioxide (CO2), ozone (O3), and nitric oxide (NO), provide a cost-effective method to kill target pests and protect stored products, specifically the red flour beetle (<i>Tribolium castaneum</i>). The study was conducted in a controlled laboratory setting, where the impact of six different MAs on <i>T. castaneum</i> reared on two diets, wheat and maize flour, was examined. These MAs consisted of varying ratios of CO2, N2, and O2. The results showed a significant correlation between gas concentration, diet, and exposure duration. 100% mortality was observed after six days under MA4 for beetles raised on wheat, whereas those on maize required eight days under MA5., while those on maize required eight days under MA5 to achieve the same mortality rate. Increased gas concentrations were associated with reduced exposure time to achieve total mortality. The findings suggest that modified atmospheres, especially those with higher CO2 concentrations, provide an effective and environmentally safer alternative for pest control in grain storage. MA’s provide a highly effective non-chemical control measure for stored-product pests. MA control systems should be further developed, improved, and applied in stored-product protection for their unique advantages, which could potentially reduce reliance on chemical pesticides and mitigate associated risks.</p>