Biological and biochemical effects of LC₅₀ of Growth Regulators (IGR's) Teflubenzuron and Lufenuron were studied against green Chrysopella carmea (Stephens) under laboratory conditions. Tested compounds were evaluated against fresh first instars by contact and feeding techniques on Corcyra cephalonica egg. LC_50s were 43.17 and 28.65 ppm, by contact technique for Teflubenzuron, and Lufenuron, respectively, but when the feeding technique was applied, the LC_50s were 31.22 and 16.71 ppm for Teflubenzuron, and Lufenuron, respectively. The biological effects of these compounds were studied on larval and pupal periods which resulted from treated first instar. The obtained results showed prolongation in developmental periods of larval and pupal stages compared with control. The latent effect of these compounds on some biochemical parameters in second instar larvae resulted from treated fresh first instar larvae were analyzed for Phenoloxidase activity, total protein, N-acetyl- glucosamine significance, and chitinase activity. The results showed a significant reduction in all biochemical parameters but chitinase was significantly high compared with control. In general, the tested compounds had significant biological and biochemical effects on immature stages of C. carnea.