This study was conducted to evaluate the toxicological effect of LC50 Hexaflumuron 10% EC on eggs of the predator mite, Euseius hutu (Pritchard & Baker) when fed on the Tetranychus urticae Koch as a prey under laboratory conditions at 25 ±1 °C and 65-70% R.H. Also, biological effect on different developmental stages of this predator emergence from treated eggs was recorded. Data proved a prolongation in the duration of different predator stages and fecundity, the larvae, protonymph and deutonymph stages lasted 3.76, 5.13 and 3.11 days/ female/ F1, and 4.1, 3.7 and 4.2 days/ female / F2, respectively, compared to 1.25, 1.49 & 2.73 days in control, while males averaged 2.23, 3.83 &3.93 days in F1and 3.23, 3 & 3 days in F2 compard to 1.55,1.48 and 3.23 days, in control.The longevity of predaceous mite under experimental conditions was found 36.5 &10.39/days for female & male in F1 and 44.5&8.6 days in F2,respectively compared to 31.0&6.58 days in control. On the other hand, food consumption of immature stages of E. hutu predator for two generation F1 &F2 averaged 9.5 & 9.13 prey/ ♀ and 7.9 & 8.2/prey ♂, respectively, compared to 15.1 &10.02 prey/, in control.