The cotton aphid, Aphis gossypii Glover is a serious plant pests causing serious damage to the cultivated crops. Entomopathogenic fungi were early used for controlling aphids. Cladosporium cladosporioides is one of the promising candidates fungus can be used as a microorganism or can be used as a source of toxins against insect pests. Present research studied the chemical constituents of methylene chloride extracts of C.  cladosporioides. It revealed 17 volatile compounds when analyzed by GC/MS technique. Also, two major compounds were isolated and identified as Pentadecanoic acid methyl ester (Compound 1) and Lupeol (Compound 2). Furthermore, the insecticidal activity of methylene chloride extracts of C.  cladosporioides was tested against both adults and nymphs of cotton aphid, A. gossypii. It showed the most effective against nymphs of  LC₅₀ of 212.2319 ppm, LC₉₀ of 1407.5663 ppm and toxicity index of 100%, while, it showed LC₅₀ of 276.75 ppm, LC₉₀ of 1902.15 ppm and toxicity index of 76.69% against adult stage.