Cowpea, Vigna unguiculata is used as human food in many parts of the world, especially in tropical and subtropical regions. The major insect pests that can cause economic loss are the cowpea beetle, Callosobruchus maculatus. To promote sustainable development, overcome climate change and minimize chemical insecticide use, evaluation of chemical insecticide (malathion) alone or combined with Gamma radiation (20Gy) was used to control cowpea beetle occurred. Radiation was applied before the chemical treatment. The results indicate there is no different effect of using insecticide alone or insecticide combined with Gamma radiation in parents, while in F1 the results indicated that there is a significant difference within days after treatment. Different concentrations of insecticide were used as well as different methods of treatment (P. value was 0.000 in all of them). Generally, when comparing means of all treatment types with the non-radiated treatment of F1, we can arrange the type of treatment according to potency as the following: an insecticide with the radiated treatment of F1 >insecticide with non-radiated and radiated of parents > radiated treatment only of parent> insecticide only of F1. Thus, the author recommended using of insecticide and Gamma rays' combination in cowpea beetle's control.