Laboratory experiments were carried out in the Insectary of the Economic Entomology Department Faculty of Agriculture Mansoura University in the incubators under constant temperature of 26±1^oC and 70±5 % R.H. to investigate some biological characteristics of the two predators Cydonia vicina nilotica Muls and Cydonia vicina isis Cr. when reared on artificial diets and natural prey Aphis gossypii Glover during 2012 year. The results revealed that the larval duration period was longer for the larvae of the two coccinellid predators reared on the three artificial diets compared with that reared on A.gossypii. The data showed that the average longevity of  C. vicina nilotica females were 47.7±4.18; 50.64±4.42 and 53.03±4.96 days while the average of  deposited eggs per predator female were 342±5.11; 599.44±6.85 and 655.18±8.75 eggs when fed on AD1 ; AD2 and AD3 respectively . The average longevity of C. vicina isis females were 45.82±3.6; 50.59±3.82 and 52.61±4.17 days while the average of deposited eggs per predator female were 410.86±5.62; 632.46±9.37 and 695.78±12.67eggs when fed on AD1 ; AD2 and AD3 respectively. The longevity period of C. vicina nilotica female was 51.8±4.16 days and the number of deposited eggs per predator female averaged 680.95±9.84 eggs, while the longevity period of C. vicina isis female was 50.51±3.65 days and the number of deposited eggs per predator female averaged 718.56±10.75 eggs when the two coccinellid predator reared on A.gossypii. As conclusion also the AD3 was the best for rearing the two coccinellid predators.  The statistical analysis showed significant difference in the fecundity of the two coccinelled predators which reared on the two artificial diets AD1; AD2 and the females which reared on A. gossypii, while the results cleared that non-significant between the AD3 and the females fed on natural prey A. gossypii. The results of this experiment assured the possibility of rearing these two predators successfully on artificial diets.