The newly hatched larvae of pink bollworm (PBW), Pectinophora gossypiella (Saunders) were fed for two days on artificial diet treated with the LC₅₀ concentration of some biocides i.e., Agrin (Bt), Ecotech-pro (Btk x Bta) and Bio-clean (Btk x Beauveria. bassiana). The survived 2^nd and 4^th instar larvae of normal appearance fed on treatments and control diets were used to study the histopathological changes of the aforementioned biocides on the fourth abdomen segment. Examination of the microtomical transverse sections of this segment showed abnormal effects in the histopathology of some organs and tissues (midgut, Malpighian tubules, fat bodies, body muscles & cuticle) of the treated larvae. Generally, the pathological effects of the tested biocides were more serious against the 2^nd instar larvae than against the 4^th one. The type and degree of these effects differed according to the tested biocide, whereas Bio-clean was the most potent one.