Three agricultural commodities namely, broad bean, cowpea and wheat flour were tested for their insect infestation by using ozone as disinfectant. The treated insect species were the bruchid beetles Callosobruchus chinensis, Bruchidius incarnates and the flour beetles, Tribolium spp. Obtained data showed that ozone concentration of 5 ppm delivered for one hour does not cause any harmful effect to larvae and adults of all tested insect pests.  For C. chinensis, at 10 ppm, adults were still resistant although larval mortality reached 6.0 %. With elevation of ozone concentration, there was a gradual increase in mortality percentage reaching, at 100 ppm, 100 and 96.6% for larvae and adults, respectively. In case of B. incarnates, the adults were also still resistant at 20 ppm, and recorded 4.0 % mortality while larval mortality reached 20.0 %. The highest mortality percentages were 96.0 and 94.0 % recorded at concentration 100 ppm for its larvae and adults, respectively. Whereas mortality percentage recorded for larvae and adults of Tribolium spp, at 20 ppm, adults were still resistant although larval mortality reached 18.0 %. However by elevation of ozone concentration to 100 ppm, mortality percentage reached, 90.0 and 78.0 % for larvae and adults, respectively. The data show that there was a steady increase in mortality of larvae and adults with the extension of exposure time to ozone reaching 100% after two hours. On the other hand, eggs and pupae of all treated insects were highly susceptible to ozone as compared to larvae and adults of the same species. For example, hundred mortality percentage for eggs and 86.0 % mortality for pupae were achieved using 5 ppm ozone for an hour. However, by using same ozone concentrations and exposure time eggs and pupae of B. incarnates recorded 96 % mortality for eggs and 89 % for pupae. To compare other forms of ozone by using ozonized water, the results indicated complete reduction in percent infestation rate on treatment with 60 ppm for one hour or 60 ppm ozonized water for one minute. Complete sterilization for all test samples from insect pest was achieved using ozone gas applied at 60 ppm for two hours or 60 ppm ozonized water for two minutes. Treatment of these commodities with ozone resulted in slight missing of protein and lipid contents but increased sugar fractions of the tested materials.