Field strains of the cotton leafworm Spodoptera littoralis (Boisd.) were collected from three Governorates (Gharbya, Kafr El-Sheikh and Behera) during 2012, 2013 and 2014 cotton seasons for monitoring of its resistance to tested biocides. The results indicate that resistance ratios RR and RC fluctuated from one year to another and from Governorate to another. During three cotton seasons the tested Bt (Dipel 2x, Dipel DF, Agerine and Protecto) showed high levels of resistance in all Governorates during 2014 cotton season which (RC) reached (13.93, 9.23 and 15.04), (9.24, 10.55 and 17.93), (6.01, 8.12 and 14.48) and (6.95, 7.08 and 8.34) in Behera, Gharbya and Kafr El-Sheikh respectively. Also, RC for Radiant compound reached to (14.07, 11.58 and 22.05) in the same Governorates. While Radical recorded medium levels of resistance (2.16, 2.29 and 4.07) and Spintor had low levels of resistance (1.21, 1.73 and 1.66) to the same field strains during cotton season 2014. The previous results suggest that Biocides Radical and Spintor may be recommended as an effective component of the future IPM programs against Spodoptera littoralis on cotton fields.