Laboratory experiments were carried out to study certain biological parameters of the two coccinellid predators, Exochomus nigromaculatus (Goeze) and Hippodamia convergens Geur. when reared on the following aphid species; Machrosiphum pisi (Harris) ; Rhopalosiphum maides (Fitch) ; Aphis durantae Theobald and Aphis nerii Boyer de Fonscolombe  under controlled conditions. The data revealed that the total developmental time from egg hatching to adult eclosion of the two coccinellid predators were differed significantly when reared on the four tested aphid species. Mortality percentage of E. nigromaculatus from egg hatching to adult emergence ranged from 9.70 % when fed on M. pisi to 15.8 % on A. nerii, while with H. convergens, it varied from 8.5 % on M. pisi to 17.96 % on A. nerii. Based on statistical analysis, the mortality percentage showed significant difference among the four aphid species. The total consumption rate per E. nigromaculatus larva from the four aphid species were 207.67 ± 4.53 ;  364.40 ± 7.56 ; 443.93 ± 8.45 and 400.85 ± 10.72 aphid individuals when reared on M. pisi ; R. maides ; A. durantae and A. nerii, respectively. The average numbers consumed from the four tested aphid species during larval stage of H. convergens  were 341.58 ± 8.15 ; 569.42 ± 19.72 ; 693.15 ± 22.54 and 468.32 ± 10.89 aphid individuals when fed on M. pisi ; R. maides ; A. durantae and A. nerii, respectively. The average number of aphids consumed per larva for the two coccinellid species was also significantly different. The aphid species have a significant effect on the longevity of adult stage of the two coccinellid predators and the fecundity of their females. The average number of eggs deposited per E. nigromaculatus female was 322.45 ± 8.75 ; 280.45 ± 6.30; 253.86 ± 4.65 and 171.62 ± 5.24 eggs when reared on M. pisi; R. maides ; A. durantae and A. nerii, respectively. While that was 650.48 ± 12.85 ; 596.78 ± 9.43 ; 542.78 ± 9.3 and 211.51 ± 5.10 eggs when the H. convergens females fed on M. pisi ; R. maides ; A. durantae and A. nerii, respectively. The statistical analysis showed that the aphid species have a highly significant effect on the female fecundity. It can be recommended that the coccinellid predators used as biological control agents against the four  aphid species tested.