A feeding trial with a total of 24 growing pigs of average 33.47kg body weigh was conducted to investigate effects of dietary supplementation with Tetrachlorvinphos on swine growth and fly control. The Experimental animals were divided into two groups of 12 gigs, 3 replicates of 4 animals each. Body weight gains and feed conversion rates were no differences between control and treatment. Maggot and fly populations were significantly reduced (P<0.05), respectively.