This study aimed mainly to estimate the resistance of the cotton leafworm Spodoptera littoralis to several bioinsecticides Agerine 6.5% WP, Protecto 9.4 %WP biotect 9.4 %, wp Dipel 2x 6.4% WP, Dipel Df 5.4 % WG and two other bioinsecticides,  Emamectin benzoate (Radical 0.5 %) EC against Spodoptera littoralis that all field strains the tested bioinsecticides used against cotton leafworm S. littoralis were calculated for both susebtable and field strains collected from six governorates namely Sharkia, Dakahlia, Behera, kafr- Elshek, Fayuom and Beni- swef in the cotton season 2019.
         The resistance ratio fluctuated from very low resistance to low resistance in some governorates to others except low of governorates RR indicated high resistance.
tested IGR^, s used against cotton leafworm S. littoralis were calculated for both susebtable and field strains collected from six governorates namely Sharkia, Dakahlia, Behera, kafr- Elshek, Fayuom, and Beni-Swef in the cotton season 2019. showed no resistance in all tested IGR, s for all Governorates, except some Governorate in some IGR, s