This investigation was carried out to investigate the behavior and persistence of thlorpyrifos-methyl, diazinon and phenthoate insecticide residues on and in tomato fruits under normal field conditions. The residues half life values (RL_so) were determined, also the efficiency of some processes i.e. washing and blanching to remove the insecticide residues from treated fruits were also conducted. The effect of tested insecticides on chemical constituents of tomato plant fruits at harvest i.e. (carbohydrate fractions content, soluble protein contents and activity of peroxidase and polyphenol oxidase) was also studied. Results indicated that the initial residues of chlorpyrifos-methyl, diazinon and phenthoate were 1.88, 1.49 and 1.77 ppm on tomato fruits after one hour from application, respectively. The corresponding residues half-life values (RLso) were 3.06, 1.25 and 7.20 days, respectively. Data also indicated that washing with tap water removed 10.38, 31.54 and 28.24% of chlorpyrifos-methyl, diazinon and phenthoate residues in tomato fruits after one hour from application, respectively. Blanching process were removed 40.45, 47.65 and 40.67% of chlorpyrifos-methyl, diazinon and phenthoate residues in tomato fruits after one hour from application, respectively. Results indicated that all tested insecticides treatment did not show any significant effect on total carbohydrates content, total soluble sugars, reducing sugars and non-reducing sugars content, total soluble protein contents and peroxidase activity and polyphenol oxidase activity in tomato fruits but phenthoate treatment had a significant decreased In total carbohydrates content in tomato fruits.