Laboratory experiments have been conducted in the Plant Protection Research Institute (Sharkia Branch) Bollworms Research Department to evaluate the effect of to study the toxic and biological effects of three synthetic organic compounds, pyrazole: (A= 3-amino-5-hydrazino-4- phenyl azo -1H-pyrazole,  B= 3-hydrazino-4- phenyl azo -5-hydroxy-1H-pyrazole and C= 1-(5-hydroxy-4- phenyl azo -1H-pyrazole-3-yl ) 3, 5-dimethylpyrazole) against the 1^st instar larvae of pink bollworm, Pectinophora gossypiella (Sound.) and 2^nd, 4^th instar larvae of cotton leafworm, Spodoptera littoralis (Boisd.) under constant conditions of (26± 1ºC. and 70 ± 5% R.H.). Data revealed that syntheticpyrazole compounds had highly toxic effect against newly hatched larvae of pink bollworm followed by 2^nd and 4^th instar larvae of S. littoralis. On the other hand, the latent effects of the  pyrazoles compounds on the two insects species were presented in increasing the duration of larval and pupal stages, Significantly decreased on larval and pupal weight of the two insects, male and female longevities and also reduced the fecundity, While the highest reduction in laid eggs recorded 103.83 eggs/female in pink bollworm followed by 123.33 eggs/female for 2^nd and 4^th instar larvae of  S. littoralis as compared with 287.25 egg/female for pink bollworm and 503.33 & 663.33 egg/female with untreated control, Also, results showed the tested chemical compounds on the hatchability rate caused decreased significantly with P. gossypiella  recorded 61.48 % with compound (A) & 55.57 ,68.21 % reduction in 2^nd, 4^th instar larvae of S. littoralis compared 88.00% for untreated moths of P. gossypiella and 63.00 , 97.47 % in 2^nd, and 4^th instar larvae for untreated moths of S. littoralis, respectively