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.1-(2-클로로-5-티아졸릴)메틸-3-메틸-2-니트로구아니딘과 N-(2-에틸헥실)-5-노르보르넨-2,3-디카르복시이미드를 유효 성분으로서 함유하는 해충 방제제는 파리에 대하여 우수한 방제 활성을 나타낸다.
