An insecticidal composition for controlling flies is provided to improve insecticidal activity, so that the excellent insecticidal effect is accomplished by using a smaller amount of the composition. The insecticidal composition for controlling flies comprises 1-(2-chloro-5-thiazolyl)methyl-3-methyl-2-nitroguanidine and N-(2-ethylhexyl)-5-norbornene-2,3-dicarboximide(MGK264), wherein the weight ratio of 1-(2-chloro-5-thiazolyl)methyl-3-methyl-2-nitroguanidine to N-(2-ethylhexyl)-5-norbornene-2,3-dicarboximide(MGK264) is 1:1 to 1:50； and the composition is used for controlling flies in a stall.
