This work aimed to study the effect of a bacterial bioagent Spinosad, an insect growth regulator Methoxyfenozide and Extrem their mixture (Spinetoram & Methoxyfenozide) were evaluated on 4^th instar larvae of Spodoptera littoralis (Boisd.) under laboratory conditions. The results indicated that LC₅₀ values of three tested compound treatments on 4^th instar larvae were determined as 7.28, 0.071 and 0.113 ppm, in Spinosad, Methoxyfenozide and extrem respectively. LC₅₀ of all treatments resulted in a prolongation of the larval duration and pupation rates were significantly decreased. The pupal weight recorded insignificant results for all treatments. Both Spinosad and Methoxyfenozide treatments insignificant differences in pupal duration, while significant differences were recorded when larvae were treated with LC₅₀ ofExtreme. The biochemical studies in 6 days after treatment of fourth instar larvae showed a significant decrease in the activity of α-esterase enzymes, while -esterase activity was significantly increased, acetylcholineterase enzyme showed a highly significant decrease in the treated with Spinosad, Methoxyfenozide, while it insignificant decrease when treated with Extreme. All treatments showed a non-significant difference in total protein contents of the whole-body homogenate of treated larvae. Results of SDS-PAGE analysis revealed that the protein profiles of S. littoralis changed after larval treatment with Spinosad, Methoxyfenozide and Extreme new proteins were observed in treated larvae.