The cotton leafworm. Spodoptera littoralis (Boisd) was reared on two artificial diets named, kidney bean and broad bean incomparable with feeding on castor bean leave under laboratory conditions i.e. 27 ± 1 º C and 70 ± 5 % R.H. The biological aspects were obtained through two generations. The two artificial diets kidney bean and broad bean were more preferred to the insect as compared to the fresh host plant (castor bean leaves). The results revealed that the mean weight of larval instars, when reared on artificial diets, was higher than that recorded when feeding on castor bean leaves and also egg deposited by females. Moreover, the duration of generation was affected by the rearing on artificial diets (31 and 33 days), respectively. On the other hand, the generation that was reared on castor bean leaves was not affected (37 days). The larval duration was higher (21days) when feeding on castor bean than the two other diets Kidney bean and broad bean which recorded (18 and 16 days), respectively, On the other hand, the adult longevity females were (7, 9 and 6 days) when feeding on Kidney bean, broad bean and castor bean leaves, respectively. It is concluded that brood bean diet is the best to conduct out the different bioassays for the cotton leafworm,