Growth, development and yield of soybean are a result of a variety's genetic potential interacting with environment and farming practices. Experiments were carried out in two locations for determining the resistance of some soybean genotypes to the cotton leaf worm. Beside that, identification of molecular genetic markers linked to insect resistance was also done. An attempt was done to get some new resistant hybrids through execution hybridization between these cultivars. Plant height, numbers of branches and pods per plant and seed yield per plant were decreased significantly by the infestation of cotton leaf worm (Spodoptera littoralis) as compared with soybean plants grown in Giza region (non ? stressed treatment). The results of SDS-PAGE revealed a total number of 21 bands with molecular weight (MW) ranging form about 319.63 to 15.568 KDa. 5 primers showed specific ISSR markers for cotton leaf worm with 6 positive markers for cotton leaf worm resistance appeared in the resistant genotypes, while 2 negative markers for susceptibility for cotton leaf worm were present in the susceptible genotypes.