There are over 3,500 species of mosquito throughout the world.But it is only thefemale of the species which bites as she searches out nourishment for her eggs.Mosquitoes find their human prey using a combination of sensory signals includinglight,shape,color,heat global atmospheric the temperatures are presently in awarming phase that began 250-300 Years ago Speculationson the potential impact of Continued on human health often focus on mosquito -bom diseases.Elementarymodels suggest that higher global temperatures will enhance their transmissionrates and extend their geographic ranges.However,the histories of three suchdiseases malaria,Yellow fever, and dengue.This experiment study was done to detectthe susceptibility of mosquito larvae to the aqueous solution of the Diazinonpesticides and to determine LC50(lethal concentration) of Diazinon on larvae andto draw the toxicity line.Eleven different concentration of Diazinon were prepared(3x10-2,15x10-3,6x10-3,4.5x10-3,3x10-3,2.1x10-3,1.5xl0-3,1.2x10-3,9x104,6x104,3x104) .The experiments were done 4 times and the average gavepercentage of death as follows (100％,92％,85％,80％,70％,66％,63％,60％,55％,25％)Regression line was drown for each experiment (1,2,3,4,and the average) and LC50 was found to be (2.8x10-3,7.2x10-4,5.2x104,1x104).Diazinonpesticide maybe used on mosquito larvae control because it is effective.More studiesare needed to determine an exact LC50 and what type of environmental oflarvae inwhich the insecticide may be used.