Resistance of cowpea aphid colony to the newest insecticide, dinotefuran was tested by selection pressure for 20 generations. Resistance ratio reached 148.8 fold in relation to susceptible strain. The LC₅₀ value of the parent (first generation) was 5.39 ppm with slope value 1.06 ±0.53 which mean that this strain was not homogenous to this insecticide. The value of LC₅₀ increased slowly with selection pressure, reached 22.24 ppm for the 10^th generation. Up to 15^th generation with the same selection pressure LC₅₀ value increased to reach to 66.19 ppm and reached to 230.71 ppm in case of 20^th generation. Resistance ratio values in relation to susceptible strain, increased until the 10^th generation to 14.34 fold, and fastly increasing to 42.7 fold and 148.8 fold to 15^th and 20^th generation respectively.                                                    Selection pressure produced some differences in total protein content and SDS- protein patterns. The analysis of esterase patterns obtained by the native- PAGE and by using α naphthyl acetate as a substrate which revealed a minor was measured.