The present studies were conducted to evaluate toxic and biological effects of some formulation compounds; XenTari, Biovar, NeemAzal, (biocids) and Jojoba oil, Orange oil (oils)against cotton leafworm, Spodoptera littoralis (Boisd.). Results clear that all compounds had toxic effect on the 2^ndinstar larvae of S. littoralis. Increasing the concentration of compounds and days post-treatment caused increase in larval mortality percentage. Jojoba oil had the highest mortality percentage (33, 42, 46, 47and 50%) and (41, 49, 53, 45 and 57%) after 1, 3, 5, 7 and 10 days from treatment by recommended and double recommended concentration as compared with 5% for control after 10 days. While the lowest mortality percentages were (13, 16, 18, 20 and 21%) and (19, 25, 28, 31 and 32%) recorded with Orange oil, respectively. 2^nd tested instar larvae were affected more than 4^nd instar larvae. These compounds showed the different effects on some aspects of S. littoralis treated as 2^nd and 4^th instar larvae and caused decrease in larval & pupal mortality percentage, larval & pupal weight, pupation & adult emergency percentage, deposited eggs/ female and hatchability percentages as compared with control. While, Dursban (O.P. Insecticide (showed the highest effects on these biological aspects as compared with previous all compounds.