The insecticidal and biological effects of three insect growth regulator (chlorfluazuron,  Tebofenozoid and pyriproxyfen) were evaluated on 4^th  instar larvae of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae). Based on the LC₅₀ values Chorofluazuron is the more toxic to S. littoralis than that of the two other compounds. Female longevity, fecundity and fertility were significantly reduced at all treatments compared to control.  Furthermore, different levels of significant changes in the total protein, carbohydrate contents of the female ovaries pre-treated as 4^th instar larvae by LC₅₀ of used IGRs were recorded. Moreover, different abnormal histological structures of ovary were noticed.